Journal articles: 'Electrical-optical modulator'

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M. A. Eid, Mahmoud, Ashraf S. Seliem, Ahmed Nabih Zaki Rashed, Abd El-Naser A. Mohammed, Mohamed Yassin Ali, and Shaimaa S. Abaza. "The key management of direct/external modulation semiconductor laser response systems for relative intensity noise control." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 2 (February 1, 2021): 968. http://dx.doi.org/10.11591/ijeecs.v21.i2.pp968-977.

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<p><span>This study outlines the management of either direct or external modulation semiconductor laser systems for the key solution of bit rate up to 25 Gb/s under relative intensity noise (RIN) control. The bias and modulation peak currents based laser rate equations are optimized to achieve max Q factor and min bit error rate (BER) using first proposed model and optical/electrical signal power, optical/electrical signal to noise ratio are also enhanced using second proposed model. The percentage enhancement ratio in max. Q-factor and min. BER using first proposed model ranges from 53.25 % to 71.63 % in compared to the previous model. In the same way, by using second proposed model, the electrical signal power at optical receiver is enhanced within the range of 48.66 % to 68.88 % in compared to the previous model. Optical signal/noise ratio (OSNR) after optical fiber cable (OFC), signal/noise ratio (SNR) after electrical filter are measured with using different electrical pulse generators and electrical modulators at the optimization stage. The first proposed model reported better max. Q and min. BER values than the previous model. In addition to the second proposed model (direct modulation) has outlined better optical/electrical signal power than the previous model, while max. Q, min. BER values are kept constant. It is found that non return to zero pulse generator has presented better signal power than other pulse generators by using second proposed model. As well as the mixed of raised cosine pulse generator with external modulator reported max. Q, min. BER with other pulse generators by using first proposed model. OSNR at OFC is optimized by using continuous phase frequency shift keying (CPFSK) electrical modulator, While SNR at optical receiver is optimized by using phase shift keying (PSK) electrical modulator.</span></p>

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Zhou, Zhipeng, Zean Li, Cheng Qiu, Yongyi Chen, Yingshuai Xu, Xunyu Zhang, Yiman Qiao, et al. "A Design of High-Efficiency: Vertical Accumulation Modulators Based on Silicon Photonics." Nanomaterials 13, no. 24 (December 16, 2023): 3157. http://dx.doi.org/10.3390/nano13243157.

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On-chip optical modulators, which are capable of converting electrical signals into optical signals, constitute the foundational components of photonic devices. Photonics modulators exhibiting high modulation efficiency and low insertion loss are highly sought after in numerous critical applications, such as optical phase steering, optical coherent imaging, and optical computing. This paper introduces a novel accumulation-type vertical modulator structure based on a silicon photonics platform. By incorporating a high-K dielectric layer of ZrO2, we have observed an increase in modulation efficiency while maintaining relatively low levels of modulation loss. Through meticulous study and optimization, the simulation results of the final device structure demonstrate a modulation efficiency of 0.16 V·cm, with a mere efficiency–loss product of 8.24 dB·V.

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Supasai, Wisut, Apirat Siritaratiwat, Chavis Srichan, Suksan Suwanarat, Narong Amorntep, Mongkol Wannaprapa, Nuttachai Jutong, et al. "Enhancing modulation performance by design of hybrid plasmonic optical modulator integrating multi-layer graphene and TiO₂ on silicon waveguides." Nanotechnology 35, no. 31 (May 17, 2024): 315201. http://dx.doi.org/10.1088/1361-6528/ad43f2.

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Abstract A novel way to enhance modulation performance is through the design of a hybrid plasmonic optical modulator that integrates multi-layer graphene and TiO2 on silicon waveguides. In this article, a design is presented of a proposed modulator based on the use of the two-dimensional finite difference eigenmode solver, the three-dimensional eigenmode expansion solver, and the CHARGE solver. Leveraging inherent graphene properties and utilizing the subwavelength confinement capabilities of hybrid plasmonic waveguides (HPWs), we achieved a modulator design that is both compact and highly efficient. The electrical bandwidth f 3dB is at 460.42 GHz and it reduces energy consumption to 12.17 fJ/bit with a modulator that functions at a wavelength of 1.55 μm. According to our simulation results, our innovation was the optimization of the third dielectric layer’s thickness, setting the stage to achieve greater modulation depths. This synergy between graphene and HPWs not only augments subwavelength confinement, but also optimizes light–graphene interaction, culminating in a markedly enhanced modulation efficiency. As a result, our modulator presents a high extinction ratio and minimized insertion loss. Furthermore, it exhibits polarization insensitivity and a greater bandwidth. Our work sets a new benchmark in optical communication systems, emphasizing the potential for the next generation of chip-scale with high-efficiency optical modulators that significantly outpace conventional graphene-based designs.

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Thomson, David J., Weiwei Zhang, Ke Li, Kapil Debnath, Shenghao Liu, Bigeng Chen, Muhammad K. Husain, et al. "Silicon photonics for high data rate applications -INVITED." EPJ Web of Conferences 238 (2020): 01005. http://dx.doi.org/10.1051/epjconf/202023801005.

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The high speed conversion of signals between the optical and electrical domains is crucial for many key applications of silicon photonics. Electro-optic modulators integrated with electronic drive amplifiers are typically used to convert an electrical signal to the optical domain. Design of these individual elements is important to achieve high performance, however a true optimisation requires careful co-design of the photonic and electronic components considering the properties of each other. Here we present our recent results in this area together with a MOSCAP type modulator with the potential for high speed, high efficiency and highly linear modulation.

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Gosciniak, Jacek. "Ultra-compact nonvolatile plasmonic phase change modulators and switches with dual electrical–optical functionality." AIP Advances 12, no. 3 (March 1, 2022): 035321. http://dx.doi.org/10.1063/5.0082094.

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Programmable photonic integrated circuits (PICs) are the foundation of on-chip optical technologies, with the optical modulators being one of the main building blocks of such programmable PICs. However, most of the available modulators suffer from high power consumption, low response time, and large footprint. Additionally, they show a large resistance modulation; thus, they require high switching voltage. In consequence, they operate much above CMOS-compatible voltages of 1.2 V and with high insertion losses. Furthermore, the state and information they carry are lost once the power is turned off—so, they are volatile. Thus, realizing modulators and phase shifters that overcome all those problems still remains a challenge. To overcome some of those limitations, the nonvolatile phase change materials implemented in the plasmonic structures are proposed that can offer many advantages as result of high electric field interaction with nonvolatile materials. Consequently, novel plasmonic nonvolatile switches proposed here can operate by phase modulation, absorption modulation, or both and under zero-static power. For the first time, the nonvolatile phase modulator is proposed that requires only 230 nm long active waveguide to attain full π phase delay with an insertion loss below even 0.12 dB. Simultaneously, under the requirements, it can operate as an amplitude modulator with an extinction ratio exceeding 2.2 dB/ μm while the insertion losses are kept below 0.185 dB/ μm. Furthermore, the heating mechanism can be based on the external heaters, internal heaters, electrical (memory) switching, or optical switching mechanism, which provide a lot of flexibility in terms of a design and requirements.

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Tahersima, Mohammad H., Zhizhen Ma, Yaliang Gui, Shuai Sun, Hao Wang, Rubab Amin, Hamed Dalir, Ray Chen, Mario Miscuglio, and Volker J. Sorger. "Coupling-enhanced dual ITO layer electro-absorption modulator in silicon photonics." Nanophotonics 8, no. 9 (August 14, 2019): 1559–66. http://dx.doi.org/10.1515/nanoph-2019-0153.

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AbstractElectro-optic signal modulation provides a key functionality in modern technology and information networks. Photonic integration has not only enabled miniaturizing photonic components, but also provided performance improvements due to co-design addressing both electrical and optical device rules. The millimeter to centimeter footprint of many foundry-ready electro-optic modulators, however, limits density scaling of on-chip photonic systems. To address these limitations, here we experimentally demonstrate a coupling-enhanced electro-absorption modulator by heterogeneously integrating a novel dual-gated indium-tin-oxide phase-shifting tunable absorber placed at a silicon directional coupler region. This concept allows utilizing the normally parasitic Kramers-Kronig relations here in an synergistic way resulting in a strong modulation depth to insertion loss ratio of about 1. Our experimental modulator shows a 2 dB extinction ratio for a just 4 μm short device at 4 V bias. Since no optical resonances are deployed, this device shows spectrally broadband operation as demonstrated here across the entire C-band. In conclusion, we demonstrate a modulator utilizing strong index change from both real and imaginary parts of active material enabling compact and high-performing modulators using semiconductor near-foundry materials.

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Feng, Song, and Bin Xue. "Micro-Nano Electro-Optic Modulator Structure Based on the Si/SiGe/Si Material." Journal of Nanoelectronics and Optoelectronics 15, no. 6 (June 1, 2020): 693–99. http://dx.doi.org/10.1166/jno.2020.2796.

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The modulation power consumption and the modulation efficiency are the key parameters of the electro-optic modulator, which directly affect the electro-optic modulator's photoelectric properties. Improving the performance of the electro-optic modulator, a micro-nano electro-optic modulator structure based on the Si/SiGe/Si material is proposed in this paper, which has low power consumption and high efficiency. After the plasma dispersion effects and the thermo-optic effects are analyzed, we can know that the performance of the electro-optic modulator could be affected by the carrier concentration and the temperature of modulator. Silicon Germanium (SiGe) material is attached to the common Silicon (Si) electro-optic modulator, and a large injection ratio is obtained from the Si/SiGe/Si double hetero-junction. With the modulation region's carrier concentration rise, and the working voltage and the power consumption of modulator all are reduced. The jugged active region structure is attached to the common Si electro-optic modulator, and the probability of inelastic collision among carriers is decreased, so the temperature rise of modulator can be reduced. The thermal-optic effects are weakened, and the modulation efficiency is increased. The simulation results show that the working voltage of the jugged SiGe modulator is less than that of the Silicon modulator at the same refractive index differences, and the jugged SiGe modulator has lower modulation power consumption; the jugged SiGe modulator's effective refractive index differences are more than the Silicon modulator's effective refractive index differences at the same working voltage, and the jugged SiGe modulator has higher modulation efficiency. Therefore, this jugged SiGe modulator is a micro-nano electro-optic modulator with lower power consumption and higher efficiency.

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Wu, Zhaoyang, Shuqing Lin, Siyuan Yu, and Yanfeng Zhang. "Submilliwatt Silicon Nitride Thermo-Optic Modulator Operating at 532 nm." Photonics 11, no. 3 (February 27, 2024): 213. http://dx.doi.org/10.3390/photonics11030213.

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Optical phase control is essential for optical beam steering applications. The silicon nitride thermo-optic modulator generally suffers from high electrical power consumption. Microresonator and multipass structures could reduce the electrical power consumption of silicon nitride thermo-optic modulators, with the drawback of a narrow operating bandwidth and high insertion loss. We demonstrate a single-pass silicon nitride thermo-optic phase modulator at 532 nm with low insertion loss and low power consumption, achieving a π phase shift power consumption down to 0.63 mW in a Mach–Zehnder switch. The rise and fall time are around 1.07 ms and 0.67 ms, respectively.

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Ogawa, Kensuke. "Increase in Modulation Speed of Silicon Photonics Modulator with Quantum-Well Slab Wings: New Insights from a Numerical Study." Photonics 11, no. 6 (June 3, 2024): 535. http://dx.doi.org/10.3390/photonics11060535.

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A Silicon Photonics modulator is a high-speed photonic integrated circuit for optical data transmission in high-capacity optical networks. Silicon Photonics modulators in the configuration of a Mach–Zehnder interferometer, in which a PN-junction rib-waveguide phase shifter is inserted in each arm of the interferometer, are studied in this paper because of their superior performance of high-quality optical data generation in a wide range of spectral bands and their simplicity in fabrication processes suitable to production in foundries. Design, fabrication, and fundamental characteristics of Silicon Photonics Mach–Zehnder modulators are reviewed as an introduction to these high-speed PICs on the Silicon Photonics platform. Modulation speed, or modulation bandwidth, is a key performance item, as well as optical loss, in the application to high-speed optical transmitters. Limiting factors on modulation speed are addressed in equations. Electrical resistance–capacitance coupling, which causes optical modulation bandwidth–optical loss trade-off, is the most challenging limiting factor that limits high-speed modulation. Expansion of modulation bandwidth is not possible without increasing optical loss in the conventional approaches. A new idea including quantum-mechanical effect in the design of Silicon Photonics modulators is proposed and proved in computational analysis to resolve the bandwidth loss trade-off. By adding high-mobility quantum-well overlayers to the side slab wings of the rib-waveguide phase shifter, the modulation bandwidth is doubled without increasing optical loss to achieve a 200 Gbaud modulation rate.

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Hu, Xiao, and Jian Wang. "Design of graphene-based polarization-insensitive optical modulator." Nanophotonics 7, no. 3 (February 23, 2018): 651–58. http://dx.doi.org/10.1515/nanoph-2017-0088.

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AbstractBy exploiting the electroabsorption effect of graphene, we present a graphene-based polarization-insensitive optical modulator. The waveguide structure consists of a silica substrate, high-index silicon strip waveguide, Si3N4dielectric spacer, two graphene layers, and two metal electrodes. The modulator performance is comprehensively studied in terms of attenuation, insertion loss, modulation depth, and bandwidth. We achieve broadband >16 dB attenuation graphene-based optical modulator over a 35 nm wavelength range (covering C band) with an imbalance of no >1 dB and insertion loss of <2 dB for transverse magnetic and transverse electric polarized modes. Moreover, the electrical properties such as energy per bit consumption (Ebit) are also studied.

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Félix Rosa, María, Lotte Rathgeber, Raik Elster, Niklas Hoppe, Thomas Föhn, Martin Schmidt, Wolfgang Vogel, and Manfred Berroth. "Design of a carrier-depletion Mach-Zehnder modulator in 250 nm silicon-on-insulator technology." Advances in Radio Science 15 (December 5, 2017): 269–81. http://dx.doi.org/10.5194/ars-15-269-2017.

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Abstract. We present the design of a single-drive Mach-Zehnder modulator for amplitude modulation in silicon-on-insulator technology with 250 nm active layer thickness. The applied RF signal modulates the carrier density in a reverse biased lateral pn-junction. The free carrier plasma dispersion effect in silicon leads to a change in the refractive index. The modulation efficiency and the optical loss due to free carriers are analyzed for different doping configurations. The intrinsic electrical parameters of the pn-junction of the phase shifter like resistance and capacitance and the corresponding RC-limit are studied. A first prototype in this technology fabricated at the IMS CHIPS Stuttgart is successfully measured. The structure has a modulation efficiency of VπL = 3.1 V ⋅ cm at 2 V reverse bias. The on-chip insertion loss is 4.2 dB. The structure exhibits an extinction ratio of around 32 dB. The length of the phase shifter is 0.5 mm. The cutoff frequency of the entire modulator is 30 GHz at 2 V. Finally, an optimization of the doping structure is presented to reduce the optical loss and to improve the modulation efficiency. The optimized silicon optical modulator shows a theoretical modulation efficiency of VπL = 1.8 V ⋅ cm at 6 V bias and a maximum optical loss due to the free carrier absorption of around 3.1 dB cm−1. An ultra-low fiber-to-fiber loss of approximately 4.8 dB is expected using the state of the art optical components in the used technology.

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Abd. Al-Salam, Abdulrazak. "Evaluation of Mtf for Fractal Optical Modulator to Znse." University of Thi-Qar Journal of Science 4, no. 4 (July 10, 2014): 152–59. http://dx.doi.org/10.32792/utq/utjsci/v4i4.685.

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Optical modulator is an important component in optical system. It is a device, which changes the angle between the vision line to the target and coordinate to electrical signal. Through this study we have designed the fractal optical modulator consisting of eighteen sector, by building a computer program (SAM1) using visual basic language. In this paper assume that nine sectors one opaque and the other nine sectors are transmitted for the light. One may consider these nine sectors also as opaque for the other regions of electro-magnetic wave spectrum. For the importance of the modulation transfer function (MTF) in testing and evaluating optical systems, it becomes the dependent measurement to know the optical systems efficiency. It has been studied for optical systems with circular aperture, where that function could evaluated the image efficiency for point object in image plane at different magnitude of transmittance. In this research, the fractal optical modulator has been designed of semiconductor material by using the fractal function. Then evaluating the values of MTF at different values of refractive index and transmittance. The best modulation of Zinc Selenide (ZnSe) material optical modulator was when transmittance (T) 73%. Where the value of MTF is maximum at refractive index η λ=11.0μm (ZnSe) equal to 2.4001. The worst case of modulation was at transmittance (T) 40%. Where the value MTF is minimum at refractive index η λ=0.54μm (ZnSe) equal to 2.6754.

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L. Jabbar, Mohammed, and Abbas Shwya Alwan. "Study of Efficiency Fractal Optical Modulator for insulator material by testing modulation transfer function." University of Thi-Qar Journal of Science 6, no. 2 (June 18, 2017): 113–20. http://dx.doi.org/10.32792/utq/utjsci/v6i2.17.

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Chopper is an important component in optical system. It represents a device, which changes the angle between the coordinate and vision lines of the target for the electrical signal. The chopper modulates the optical signal by a frequency dependent on the number and sectors shapes. The optical modulator takes shapes of various circular due to the need for it. Through this study we have designed the fractal optical modulator its two circles inner and outer, each circle involving in eighteen sectors, by building a computer program using visual basic language. In this paper, we assume that nine sectors one opaque and the other nine sectors are transmitted for the light. Even though the importance of the modulation transfers function (MTF) in testing and evaluating optical systems, it becomes the dependent measurement to know efficiency of the optical systems. It has been studied for optical systems at circular apertures, where that function could evaluate the image efficiency for point object in image planes at different magnitude of a radius and time. The fractal reticle have been designed of insulator material by using the fractal function. Then , evaluating the values of MTF at different values of a radius and time. Also we studied relation between number of sections and spatial frequency.

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Mittal, Ashok, and Asok De. "Integrated Balanced BPSK Modulator for Millimeter Wave Systems." Active and Passive Electronic Components 2007 (2007): 1–4. http://dx.doi.org/10.1155/2007/69515.

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This paper details the design of integrated balanced PSK modulator using finline coplanar line hybrid junction. The PSK signal output is in suspended stripline with incident wave carrier in finline. Schottky barrier Diode MA4E2037 has been used for modulation. The balanced configuration offers high isolation between the carrier input port and the modulated carrier output port and thus the pulse width variations and amplitude deviations are suppressed. An insertion loss imbalance of±1.5 dB with an average loss of 2 dB in the two switching states has been achieved over 38.9 to 40 GHz. The phase imbalance is±10 degrees with phase switching from 180 to 199 degrees As the PSK output signal is in suspended stripline, two BPSK modulators can be easily combined together to work as QPSK modulator.

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Belhassen, Jérémy, Zeev Zalevsky, and Avi Karsenty. "Optical Polarization Sensitive Ultra-Fast Switching and Photo-Electrical Device." Nanomaterials 9, no. 12 (December 7, 2019): 1743. http://dx.doi.org/10.3390/nano9121743.

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Ultra-fast electrical switches activated with an optical-polarized light trigger, also called photo-polarized activated electrical switches, are presented. A set of new transistor circuits is switched by light from above, illuminating deep V-grooves, whose angle is sensitive to the polarization of the incident. Thus, this application may serve for encryption/decryption devices since the strongest electrical responsivity is only obtained for very specific spatial polarization directions of the illumination beam. When this V-groove is sufficiently narrow, the device mainly responds to one polarization and not to the other. In such a way, electrons are generated only for one specific polarization. While the nature of the data remains electronic, the modulation control is optic, creating a photo-induced current depending on the polarization direction. This coupled device acts as a polarization modulator as well as an intensity modulator. The article focuses on the integration of several devices in different configurations of circuitry: dual, triple, and multi-element. Case studies of several adjacent devices are presented with varying critical variables, such as the V-groove aperture dimensions. Analytical models and complementary numerical analyses are presented for the future smooth integration into Complementary Metal-Oxide-Semiconductor (CMOS) technology.

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Bhowmik, Tanmay, and Debabrata Sikdar. "Parallel directional coupler based dual-polarization electro-absorption modulator using epsilon near-zero material." Journal of Physics D: Applied Physics 55, no. 13 (December 31, 2021): 135107. http://dx.doi.org/10.1088/1361-6463/ac4455.

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Abstract Electro-optical modulation, where a radio frequency signal can be encoded in an optical field, is crucial to decide the overall performance of an integrated photonics system. Due to the growing internet penetration rate worldwide, polarization-division-multiplexing (PDM) technique has emerged to increase the link capacity, where polarization-independent modulators are desirable to reduce system complexity. In this study, we propose a novel parallel directional coupler based dual-polarization electro-absorption modulator based on epsilon-near-zero (ENZ) material. The proposed design is capable of independent and synchronized modulation of two fundamental modes viz. transverse magnetic (TM) and transverse electric (TE) mode of a standard silicon (Si) rib waveguide. Indium-tin-oxide (ITO)–Si based two parallel hybrid plasmonic waveguides (HPW1 and HPW2) are placed such that fundamental TM (TE) mode of the input bus waveguide can be coupled to HPW1 (HPW2). The ENZ-state of ITO, acquired upon two independent electrical gating, enables large modulation depth by utilizing enhancement of electric field at the absorptive carrier accumulation layer. With a 27 μm active length, the extinction ratio (ER) of the proposed design is 10.11 dB (9.66 dB) for TM (TE) modulation at 1550 nm wavelength. This results in a 0.45 dB ER-discrepancy and indicates the polarization-insensitive nature of the modulator. The insertion losses and modulation bandwidths of our design are less than 1 dB and more than 100 GHz, respectively, for both polarizations over the entire C-band of wavelength. The proposed design can find potential applications in the PDM-enabled integrated photonics systems and high speed optical interconnections at data center networks.

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Liu, Zhe, Dayong Wang, Weimin Zhu, Jing Zhang, Yunxin Wang, Jinchuan Yao, and Yu Zhang. "Microwave Photonics Broadband Doppler Velocity Simulator with High Spurious Suppression Ratio by Using Serrodyne Modulation." Photonics 11, no. 4 (April 12, 2024): 357. http://dx.doi.org/10.3390/photonics11040357.

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A Doppler velocity simulation method based on serrodyne modulation is proposed to achieve the frequency shift from hundred hertz to megahertz. One sub-phase modulation (PM) in a dual-parallel dual-drive Mach–Zehnder modulator loads a sawtooth signal to achieve a small frequency shift of the optical carrier. The other three sub-PMs implement carrier-suppressed double-band modulation of the RF signal. The RF signal is directly coupled from the receiving antenna to the modulator’s RF port without any electrical devices like a 90° hybrid, which ensures a broad operational bandwidth of the system. After filtering out one of the RF modulation sidebands by an optical filter, Doppler frequency shifting (DFS) is realized through frequency beating. The half-wave voltage of modulators rapidly decreases at low frequency shifts, leading to an increase in spurious signals. In order to improve the spurious suppression ratio (SSR) of DFS, a digital pre-distortion compensation based on the measured half-wave voltage is implemented in the frequency domain. Experimental results show that SSRs are larger than 35 dB when frequency shifts range from 0.1 kHz to 1 MHz. The RF operation bandwidth covers 2–40 GHz. The effectiveness of a Doppler velocity simulator is evaluated, and the simulation velocity error is less than 0.06 km/h. The proposed method has potential applications in both broadband electronic warfare and traffic metering applications.

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Deshours, Frédérique, Anne-Laure Billabert, Catherine Algani, Fabrice Blache, Christian Rumelhard, and Georges Alquié. "A 40 Gbps electro-absorption modulator integrated laser modeling method for optical transmitter in ultra-wide band radio-over-fiber systems." International Journal of Microwave and Wireless Technologies 1, no. 6 (December 2009): 511–19. http://dx.doi.org/10.1017/s1759078709990791.

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The great interest of optical fiber links in communicating systems especially in ultra-wide band (UWB) communications has grown up in the last decade and requires co-simulation for mixed circuits design exploiting both optical and microwave domains. In this paper, we report an original modeling method of an electro-absorption modulator associated with a distributed-feedback laser to simulate an optical transmitter of an UWB over fiber system. Large signal optoelectronic device models can be developed and implemented in a high-frequency simulator, such as advanced design system-Ptolemy to analyze the performances of fiber radio links and study the impact of the transmitter characteristics. This specific simulation way, taking into account precisely electrical characteristics of both electrical and optical circuits, links two different frequency domains by coupling electrical and optical modules in the same system simulator. Therefore, a complete simulation of an UWB multi-band orthogonal frequency division multiplexing signal transmission over fiber with an external modulator is investigated.

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Epikhin, V. M., M. M. Mazur, A. V. Ryabinin, P. V. Kamaushkin, and L. I. Mazur. "Acousto-optic modulators/frequency shifters with single-mode optic fibers." Journal of Physics: Conference Series 2127, no. 1 (November 1, 2021): 012037. http://dx.doi.org/10.1088/1742-6596/2127/1/012037.

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Abstract Acousto-optic modulators/frequency shifters based on TeO2 crystals with single-mode optical fibers supporting and not supporting polarization for collimated and focused light beams at radiation wavelengths of 785, 1064, 1550 nm have been developed, produced and experimentally investigated. The mechanisms of formation and methods of expanding the working band of the modulator are determined. A double-crystal acousto-optic laser emission frequency shifter with an working bandwidth of ≈40 MHz has been created. Single-crystal modulators based on collimated beams with a frequency band of ≈10 MHz are considered. A single-crystal modulator with a focused light beam with a switching time of ≈ 18 ns and an extended reception band of ≈ 40 MHz is investigated. It is shown that a light beam focusing makes it possible to implement a modulator with a minimum switching time of ≈ (2-3) ns. This value is limited by electrical breakdown of the ultrasonic wave transmitter.

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Guan, Mengyuan, Lu Wang, Fangping Li, Xiaoyu Chen, Ming Li, Ninghua Zhu, and Wei Li. "Photonic Generation of Background-Free Phase-Coded Microwave Pulses with Elimination of Power Fading." Photonics 10, no. 1 (January 7, 2023): 66. http://dx.doi.org/10.3390/photonics10010066.

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We report a novel photonic scheme to generate background-free phase-coded microwave pulses with elimination of power fading by cascading a dual-polarization dual-parallel Mach–Zehnder modulator (DP-DPMZM) and a polarization modulator (PolM). The DP-DPMZM is driven by a radio frequency (RF) signal to generate two first-order optical sidebands with an orthogonal polarization state, while the PolM is driven by a three-level electrical coding signal. By properly adjusting the polarization state, a series of background-free frequency-doubled phase-coded microwave pulses can be generated after optical-to-electrical conversion. Benefiting from the carrier-suppressed single-sideband (CS-SSB) modulation, the proposed signal generator can suppress the chromatic-dispersion-induced power-fading effect, which has excellent potential for long-distance fiber transmission. In addition, the system can directly generate phase-coded microwave signals in pulse mode by truncating continuous wave (CW) microwave signals. Moreover, the microwave signal generator has wideband tunability since no optical filter is involved in our scheme. The proposed method was theoretically analyzed and experimentally verified. Phase-coded microwave pulses centered at 14 GHz and 19.2 GHz with a bit rate of 0.5 Gb/s were successfully generated.

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Josten, Arne, Benedikt Baeuerle, Romain Bonjour, Wolfgang Heni, and Juerg Leuthold. "Optical Transmitters without Driver Amplifiers—Optimal Operation Conditions." Applied Sciences 8, no. 9 (September 14, 2018): 1652. http://dx.doi.org/10.3390/app8091652.

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An important challenge in optical communications is the generation of highest-quality waveforms with a Mach–Zehnder modulator with a limited electrical swing (Vpp). For this, we discuss, under limited Vpp, the influence of the waveform design on the root-mean-square amplitude, and thus, the optical signal quality. We discuss the influence of the pulse shape, clipping, and digital pre-distortion on the signal quality after the electrical-to-optical conversion. Our simulations and experiments, e.g., suggest that pre-distortion comes at the expense of electrical swing of the eye-opening and results in a lower optical signal-to-noise ratio (OSNR). Conversely, digital post-distortion provides operation with larger eye-openings, and therefore, provides an SNR increase of at least 0.5 dB. Furthermore, we find that increasing the roll-off factor increases the electrical swing of the eye-opening. However, there is negligible benefit of increasing the roll-off factor of square-root-raised-cosine pulse shaped signals beyond 0.4. The findings are of interest for single-channel intensity modulation and direct detection (IM/DD) links, as well as optical coherent communication links.

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Kareem, Marwa M., Sameer A. S. Lafta, Hadi Fakhir Hashim, Raed Khalid Al-Azzawi, and Adnan Hussein Ali. "Analyzing the BER and optical fiber length performances in OFDM RoF links." Indonesian Journal of Electrical Engineering and Computer Science 23, no. 3 (September 1, 2021): 1501. http://dx.doi.org/10.11591/ijeecs.v23.i3.pp1501-1509.

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Radio over fiber (RoF) can be assessed as a system of most convenient combination of optical fiber and radio signals. The technique of orthogonal frequency division multiplexing (OFDM) considers as a data distribution over a huge number of carriers having spaced from each other with specific frequencies at overlap bands. Hence incorporates OFDM with the optical fiber, OFDM-RoF system can be increased the modulation RF access capacity besides high-speed data transmission, it considers a broadband communication trend of the current and future applications specifically for 5G mobile. The optical network scenarios of various RF can be model with optisystem software, and OFDM in addition to use a section of the orthogonal multiplex frequency of 16-quadrature amplitude modulation (QAM) RF modulating signal. In the optical domain, Mach-Zehnder modulator (MZM) optical modulators are used to carry out different results with different fiber lengths. An OFDM-RoF wireless communication system considers as advanced data rate transmission achievement by minimum delays. The essential goal of this paper is for identifying the minimum bit error rate (BER) for the 16-QAM modulation with varying fiber length. The OFDM-RoF system can be able for realizing a fiber length 100 km with a restricted decreasing in the received power so that the constellation noise is became greater despite of applying electrical amplification and optical amplification.

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Sun, Feiying, Changbin Nie, Xingzhan Wei, Hu Mao, Yupeng Zhang, and Guo Ping Wang. "All-optical modulation based on MoS₂-Plasmonic nanoslit hybrid structures." Nanophotonics 10, no. 16 (October 15, 2021): 3957–65. http://dx.doi.org/10.1515/nanoph-2021-0279.

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Abstract Two-dimensional (2D) materials with excellent optical properties and complementary metal-oxide-semiconductor (CMOS) compatibility have promising application prospects for developing highly efficient, small-scale all-optical modulators. However, due to the weak nonlinear light-material interaction, high power density and large contact area are usually required, resulting in low light modulation efficiency. In addition, the use of such large-band-gap materials limits the modulation wavelength. In this study, we propose an all-optical modulator integrated Si waveguide and single-layer MoS2 with a plasmonic nanoslit, wherein modulation and signal light beams are converted into plasmon through nanoslit confinement and together are strongly coupled to 2D MoS2. This enables MoS2 to absorb signal light with photon energies less than the bandgap, thereby achieving high-efficiency amplitude modulation at 1550 nm. As a result, the modulation efficiency of the device is up to 0.41 dB μm−1, and the effective size is only 9.7 µm. Compared with other 2D material-based all-optical modulators, this fabricated device exhibits excellent light modulation efficiency with a micron-level size, which is potential in small-scale optical modulators and chip-integration applications. Moreover, the MoS2-plasmonic nanoslit modulator also provides an opportunity for TMDs in the application of infrared optoelectronics.

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Turpaud, Victor, Thi-Hao-Nhi Nguyen, Natnicha Koompai, Jacopo Frigerio, Jean-René Coudevylle, Cédric Villebasse, David Bouville, et al. "Tunable electro-optic frequency-comb generation around 8 µm wavelength." EPJ Web of Conferences 287 (2023): 07008. http://dx.doi.org/10.1051/epjconf/202328707008.

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Electro-optic frequency-comb is an interesting method for comb generation as it offers the possibility to electrically tune the generated frequency-comb by simply tuning the electrical signal applied on the modulator. Integrated modulators operating in a wide spectral range in the mid-IR have been demonstrated recently, relying on free carrier plasma dispersion effect in a Schottky diode embedded in a Ge-rich graded SiGe waveguide. Such integrated mid-infrared modulators have been used to generate electro-optic frequency-combs with more than 200 lines around the 8 µm wavelength optical carrier.

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Xu, Yin, Feng Li, Zhe Kang, Dongmei Huang, Xianting Zhang, Hwa-Yaw Tam, and P. Wai. "Hybrid Graphene-Silicon Based Polarization-Insensitive Electro-Absorption Modulator with High-Modulation Efficiency and Ultra-Broad Bandwidth." Nanomaterials 9, no. 2 (January 27, 2019): 157. http://dx.doi.org/10.3390/nano9020157.

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Polarization-insensitive modulation, i.e., overcoming the limit of conventional modulators operating under only a single-polarization state, is desirable for high-capacity on-chip optical interconnects. Here, we propose a hybrid graphene-silicon-based polarization-insensitive electro-absorption modulator (EAM) with high-modulation efficiency and ultra-broad bandwidth. The hybrid graphene-silicon waveguide is formed by leveraging multi-deposited and multi-transferred methods to enable light interaction with graphene layers in its intense field distribution region instead of the commonly used weak cladding region, thus resulting in enhanced light–graphene interaction. By optimizing the dimensions of all hybrid graphene-silicon waveguide layers, polarization-insensitive modulation is achieved with a modulation efficiency (ME) of ~1.11 dB/µm for both polarizations (ME discrepancy < 0.006 dB/µm), which outperforms that of previous reports. Based on this excellent modulation performance, we designed a hybrid graphene-silicon-based EAM with a length of only 20 µm. The modulation depth (MD) and insertion loss obtained were higher than 22 dB and lower than 0.23 dB at 1.55 µm, respectively, for both polarizations. Meanwhile, its allowable bandwidth can exceed 300 nm by keeping MD more than 20 dB and MD discrepancy less than 2 dB, simultaneously, and its electrical properties were also analyzed. Therefore, the proposed device can be applied in on-chip optical interconnects.

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Bin Zhang, Bin Zhang, Shiyu Liu Shiyu Liu, Xianzhu Tang Xianzhu Tang, and and Jian'gang Lu and Jian'gang Lu. "Adaptive modulation system for liquid crystal phase modulator." Chinese Optics Letters 14, no. 9 (2016): 090604–90607. http://dx.doi.org/10.3788/col201614.090604.

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Huang, Tao, Zhiqiang Fan, Jun Su, and Qi Qiu. "Time Jitter Analysis of an Optical Signal Based on Gated On-Off Optical Sampling and Dual-Dirac Modeling." Electronics 12, no. 3 (January 27, 2023): 633. http://dx.doi.org/10.3390/electronics12030633.

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A time jitter analysis method for an optical signal based on gated on-off optical sampling and dual-Dirac modeling is proposed and demonstrated experimentally. The optical signal under test is firstly sampled by an optical sampling pulse train generated through the gating on-off modulation of a Mach–Zehnder modulator (MZM). The sampled pulse is then broadened using optical true-time delay and electrical low-pass filtering to reduce its bandwidth to match the sample rate of a low-speed electrical analog-to-digital converter (ADC), which is used to quantify the sampled pulse. An eye diagram is obtained from the quantified data and used to plot a time jitter histogram. Finally, the dual-Dirac model is introduced to analyze the time jitter histogram to obtain the total jitter (TJ), including the deterministic jitter (DJ) and random jitter (RJ). In the experiment, a 19.05 ps TJ, including a 13.20 ps DJ and a 5.85 ps RJ, is measured for a 2.5 GHz optical signal using the proposed time jitter analysis method. The results agree well with those measured with a commercial real-time oscilloscope.

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Armel, Bimogo Joseph, Essiben Dikoundou Jean-Francois, and Ihonock Eyembe Luc. "Comparative evaluation of optical amplifiers in passive optical access networks." Indonesian Journal of Electrical Engineering and Computer Science 27, no. 3 (September 1, 2022): 1452. http://dx.doi.org/10.11591/ijeecs.v27.i3.pp1452-1461.

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In this paper, the parameters of optical amplifiers are evaluated using numerical methods with the Optisystem software. The main objective of this evaluation is the implementation of an optical telecommunication architecture, able to push back the current limits, due to a more and more restricted bandwidth following a demand which does not stop growing. We start from a study of the classical architecture of an optical telecommunication network with an external modulation provided by the mach zehnder modulator, the non return to zero (NRZ) coding, a pseudo random bit generator and a continuous wave (CW) laser diode of frequency 193.1 THz. The results obtained show a transmission possibility at 30.8 dBm and an output power of 25 dBm (316 mW) with an electrical rate signal to noise (SNR) and optical rate signal to noise (OSNR) beyond 34 dBm. The successive integration of the different amplifiers will improve these results with a gain of more than 10 dBm and also provide a better signal quality.

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Hou, Songyan, Hao Hu, Zhihong Liu, Weichuan Xing, Jincheng Zhang, and Yue Hao. "High-Speed Electro-Optic Modulators Based on Thin-Film Lithium Niobate." Nanomaterials 14, no. 10 (May 16, 2024): 867. http://dx.doi.org/10.3390/nano14100867.

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Electro-optic modulators (EOMs) are pivotal in bridging electrical and optical domains, essential for diverse applications including optical communication, microwave signal processing, sensing, and quantum technologies. However, achieving the trifecta of high-density integration, cost-effectiveness, and superior performance remains challenging within established integrated photonics platforms. Enter thin-film lithium niobate (LN), a recent standout with its inherent electro-optic (EO) efficiency, proven industrial performance, durability, and rapid fabrication advancements. This platform inherits material advantages from traditional bulk LN devices while offering a reduced footprint, wider bandwidths, and lower power requirements. Despite its recent introduction, commercial thin-film LN wafers already rival or surpass established alternatives like silicon and indium phosphide, benefitting from decades of research. In this review, we delve into the foundational principles and technical innovations driving state-of-the-art LN modulator demonstrations, exploring various methodologies, their strengths, and challenges. Furthermore, we outline pathways for further enhancing LN modulators and anticipate exciting prospects for larger-scale LN EO circuits beyond singular components. By elucidating the current landscape and future directions, we highlight the transformative potential of thin-film LN technology in advancing electro-optic modulation and integrated photonics.

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Zou, Weiwen, Lei Yu, Shuo Yang, and Jianping Chen. "Optical pulse compression reflectometry based on single-sideband modulator driven by electrical frequency-modulated pulse." Optics Communications 367 (May 2016): 155–60. http://dx.doi.org/10.1016/j.optcom.2016.01.034.

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Xu, Bin, Yao Ji, Kai Liu, and Jinhua Li. "Piezoelectric MEMS Mirror with Lissajous Scanning for Automobile Adaptive Laser Headlights." Micromachines 13, no. 7 (June 25, 2022): 996. http://dx.doi.org/10.3390/mi13070996.

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The emergence of smart headlights with reconfigurable light distributions that provide optimal illumination, highlight road objects, and project symbols to communicate with traffic participants further enhances road safety. Integrating all these functions in a single headlight usually suffers from issues of bulky multi-functional add-on modules with high cost or the use of conventional spatial light modulators with low optical efficiency and complex thermal design requirements. This paper presents a novel laser headlight prototype based on biaxially resonant microelectromechanical systems (MEMS) mirror light modulator for mapping blue laser patterns on phosphor plate to create structured white illumination and tunable road projection. The proposed headlight prototype system enables reconfigurable light distribution by leveraging laser beam scanning with fewer back-end lens and simple thermal design requirements. Built with thin-film lead zirconate titanate oxide (PbZrTiO3) actuators, the MEMS mirror achieved high-frequency biaxial resonance of 17.328 kHz, 4.81 kHz, and optical scan angle of 12.9°. The large mirror design of 2.0 mm facilitates more refined resolvable projection pixels, delivers more optical power, and provides moderate optical aperture to possibly serve as the common spatial light modulator of headlight and the light detection and ranging (LiDAR) towards all-in-one integration. The carefully designed bi-axial resonant frequency improves the device’s robustness by offsetting the lowest eigenmode away from the vehicle vibration. By establishing the laser headlight prototype systems of both 1D and 2D scanning modes, a mathematical model of laser modulation and MEMS electrical control principles of Lissajous scanning are proposed to tune the projection pattern density and shapes. It laid the foundation for developing a laser scanning control system with more complex project functions and prompting the application of MEMS for compact headlight system that addresses night driving visibility, eliminates glare effect, and renders interactive projection capabilities.

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Ding, Jianfeng, Sizhu Shao, Lei Zhang, Xin Fu, and Lin Yang. "Silicon 16-QAM optical modulator driven by four binary electrical signals." Optics Letters 42, no. 8 (April 13, 2017): 1636. http://dx.doi.org/10.1364/ol.42.001636.

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Zhai, Kunpeng, Xuhua Cao, Sha Zhu, Huashun Wen, Yinfang Chen, Ya Jin, Xinyan Zhang, Wei Chen, Jiabin Cui, and Ninghua Zhu. "An All-Optical Microwave Frequency Divider with Tunable Division Factors Based on DP-DPMZM." Photonics 10, no. 2 (January 30, 2023): 138. http://dx.doi.org/10.3390/photonics10020138.

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Based on a dual-polarization dual-parallel Mach–Zehnder modulator (DP-DPMZM), an all-optical frequency divider is proposed and experimentally demonstrated. Two radio frequency (RF) signals are modulated on an optical carrier to work as a dual-beam master laser (ML). The optical signals of the ML are injected into a distributed feedback (DFB) laser to initiate the period-two (P2) state oscillation. By beating the output of the slave laser (SL) via circulator in a photodetector, a frequency divider with tunable factors can be achieved. The innovation of the scheme lies in having a simple structure and only requires optical devices, which is operated in wide RF frequency range without any electrical amplifiers before the photodetector to increase the conversion gain. Experiment results also demonstrate that the frequency division factors can be adjusted.

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Chen, Yifei, Mingxin Liu, Hongsheng Niu, Chen Guo, Shangqing Shi, Wei Cheng, Jin Wang, et al. "Breaking efficiency-bandwidth limits of integrated silicon modulator using rib waveguide slab region doping design." Journal of Optics 26, no. 10 (September 6, 2024): 105801. http://dx.doi.org/10.1088/2040-8986/ad7519.

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Abstract Doping optimization in the slab waveguide region of a silicon photonic (SiP) modulator has always been considered to balance the optical loss and electrical resistance–capacitance constant. We found that the AC PN junction capacitance could be significantly decreased by specific doping concentrations in the slab areas. Benefiting from this effect, microwave losses are reduced and the electro-optic (EO) bandwidth is increased. As a proof-of-concept, we propose a silicon modulator based on a conventional lateral PN junction with optimized doping in the waveguide slab region. The simulation results show that a 3 dB-EO bandwidth exceeds 100 GHz can be achieved with a modulation length of 2 mm. In addition, the modulation efficiencies are 1.26 V·cm and 1.45 V·cm under −4 V bias and −6 V bias, respectively. This design shows the potential of high-speed signal transmission in SiPs.

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KUKHTAREV, N., T. KUKHTAREVA, M. E. EDWARDS, B. PENN, D. FRAZIER, H. ABDELDAYEM, P. P. BANERJEE, T. HUDSON, and W. A. FRIDAY. "PHOTOINDUCED OPTICAL AND ELECTRICAL HIGH-VOLTAGE PULSATIONS AND PATTERN FORMATION IN PHOTOREFRACTIVE CRYSTALS." Journal of Nonlinear Optical Physics & Materials 11, no. 04 (December 2002): 445–53. http://dx.doi.org/10.1142/s0218863502001164.

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We review our results on conversion of CW laser Ar-ion beam power into pulsating multi-channel outputs: optical, electric and piezoelectric with simultaneous dynamic pattern formation. We show, that electrical pulsations generate high-voltage signals that may be used as a driving voltage for the conventional electro-optical modulator. We have also demonstrated the possibility of synchronization of two optical pulsators, through regulated optical coupling in a photorefractive LiNbO3 crystal. Spatial distribution of scattered light is self-organized in different patterns (hexagonal and cross-type).

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Chen, Xu, Xinqiao Chen, Siyuan Dai, Bin Li, and Ling Wang. "A Novel Inserting Pilot Radio over Fiber System without the Bit Walk-Off Effect for the Generation and Distribution of Frequency 16-Tupling Millimeter Waves by Mach–Zehnder Modulators." Photonics 11, no. 5 (April 28, 2024): 410. http://dx.doi.org/10.3390/photonics11050410.

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A novel inserting pilot scheme to generate and distribute a frequency 16-tupling millimeter wave (MMW) radio over fiber (ROF) system without the bit walk-off effect via Mach–Zehnder modulators (MZMs) is proposed. The operation principle is analyzed and the feasibility of our proposed scheme is verified by simulation test. The main part of our scheme is a ±8th-order sidebands generator (SG), which is constructed by four MZMs connected in parallel. In the back-to-back (BTB) transmission case, by properly adjusting the voltage and initial phase of the radio frequency (RF) drive signals of the MZMs, ±8th-order sidebands are generated by the SG. In the data transmission case, the data signal is first split into two beams, one of which modulates the RF drive signal with an electrical phase modulator (PM) while the other is amplified by an electrical gainer (EG), and then the two beams are combined into one and used as the composite RF drive signal of the MZMs. By adjusting the modulation index of the PM and the gain of the EG, the data signal can only be modulated to the +8th-order sideband of the output of the SG. The optical carrier from the continuous wave (CW) laser is split into two paths: one is sent into the SG, and the other is used as a pilot signal. The output signal of SG is combined with the pilot signal and is transmitted to the base station (BS) via optical fiber. At the BS, the pilot signal is filtered out by a fiber Bragg grating (FBG) and used as the carrier for the uplink for carrier reuse. After filtering out the pilot, the signal from the FBG, which is composed of ±8th-order sidebands, is injected into a photodetector, and a frequency 16-tupling MMW with downlink data is generated. The key parameters’ influence on the bit error rate (BER) and Q factor in the system is also analyzed. Our scheme can not only effectively overcome the bit walk-off effect caused by optical fiber chromatic dispersion and greatly increase the fiber transmission distance but can also effectively improve the performance and the tunability of system. Therefore, it has important application prospects in ROF systems.

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Wang, Dongfei, Xiangqing Wang, Xiaokun Yang, Bin Liu, Lan Zhang, Zufang Yang, and Baohong Wu. "A Novel Frequency Double Millimeter Wave Signal Generation Scheme with Optical Carrier Suppression Based on a Single Polarization Modulator." Journal of Nanoelectronics and Optoelectronics 17, no. 6 (June 1, 2022): 934–38. http://dx.doi.org/10.1166/jno.2022.3273.

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In the work, a novel and simple double frequency millimeter wave (mm-wave) signal generation scheme with optical carrier suppression (OCS) enabled by a single polarization modulator is proposed. The scheme is a simple structure to achieve the mm-wave signal generation, and the core of which just depend on a polarization modulator and two linear polarizers, and electronic circuits is needless to control the drift of modulator bias points and no optical filters is needed to filter out undesirable harmonics. The polarization angle of the first linear polarizer (POL-1) is set to 45°, the polarization angle of the second linear polarizer (POL-2) is set to −45° to suppress even order optical sidebands, and the modulation index of polarization modulator (POLM) is adjusted to realize small signal modulation. Based on mathematical reasoning and computer simulation, the proposed scheme is well feasible. Simulation results show that using 20 GHz RF signal to drive the POLM, 40 GHz mm-wave signal with 47 dB optical sideband suppression ratio (OSSR) and 41.19 dB radio frequency sideband suppression ratio (RFSSR) was obtained.

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Chen, Jigen, Mengli Liu, Ximei Liu, Yuyi Ouyang, Wenjun Liu, and Zhiyi Wei. "The SnSSe SA with high modulation depth for passively Q-switched fiber laser." Nanophotonics 9, no. 8 (April 22, 2020): 2549–55. http://dx.doi.org/10.1515/nanoph-2020-0113.

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AbstractIV–VI semiconductors have attracted widespread attention in basic research and practical applications, because of their electrical and optoelectronic properties comparable to graphene. Herein, an optical modulator based on SnSSe with strong nonlinearity is prepared by chemical vapor transfer method. The modulation depth of proposed SnSSe saturable absorber (SA) is up to 57.5%. By incorporating SnSSe SA into the laser, the Q-switched pulses as short as 547.8 ns are achieved at 1530.07 nm. As far as we know, this is the first successful application of SnSSe in Q-switched lasers. Our investigation not only prove the optical nonlinearity of SnSSe, but also reveal the potential of SnSSe SA in ultrafast photonics.

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Lowery, Arthur James. "All-optical DAC using counter-propagating optical and electrical pulses in a Mach-Zehnder modulator." Optics Express 22, no. 21 (October 17, 2014): 26429. http://dx.doi.org/10.1364/oe.22.026429.

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Stepanenko, Mikhail, Igor Yunusov, Vadim Arykov, Pavel Troyan, and Yury Zhidik. "Multi-Parameter Optimization of an InP Electro-Optic Modulator." Symmetry 12, no. 11 (November 21, 2020): 1920. http://dx.doi.org/10.3390/sym12111920.

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In this article, a method for indium phosphide (InP) electro-optic modulator (EOM) optimization is introduced. The method can be used for the design and analysis of an EOM based on the Mach-Zehnder interferometer (MZI) design. This design is based on the division of the input optical signal into two optical paths and then, after processing, it combines the light into a single waveguide. The symmetry of the structure can provide state-of-the-art EOM characteristics with a push-pull control signal. Using a traveling wave electrode (TWE) design as a starting point, the authors varied the heterostructure design and optical waveguide parameters to obtain the optimal values of initial optical loss, evenness of the initial optical loss in the operating wavelength range, and the extinction ratio and length of the modulator arm. The key features of the proposed optimization method include the following: all independent input parameters are linked into a single system, where the relationship between the electrical and optical parameters of the modulator is realized; all physically realizable combinations of the input parameters are available for analysis; and EOM optimization is possible for one target parameter or for a group of target parameters. The results of the EOM optimization using the described method are presented.

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Zeng, Hongxin, Sen Gong, Lan Wang, Tianchi Zhou, Yaxin Zhang, Feng Lan, Xuan Cong, et al. "A review of terahertz phase modulation from free space to guided wave integrated devices." Nanophotonics 11, no. 3 (December 19, 2021): 415–37. http://dx.doi.org/10.1515/nanoph-2021-0623.

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Abstract In the past ten years, terahertz technology has developed rapidly in wireless communications, spectroscopy, and imaging. Various functional devices have been developed, such as filters, absorbers, polarizers, mixers, and modulators. Among these, the terahertz phase modulation is a current research hotspot. It is the core technology to realize flexible control of the terahertz wavefront, beam scanning, focusing deflection. It is indispensable in terahertz wireless communication, high-resolution imaging, and radar systems. This review summarizes the research progress of terahertz phase modulators from the two major types: free space and guided wave integration. Among these, the free space terahertz phase modulator is realized by combining the tunable materials and artificial metasurfaces. Based on different types of tunable materials, the terahertz free space phase modulator combining the semiconductor, liquid crystal, phase change materials, graphene, and other two-dimensional materials are introduced, and the influence of different materials on the phase modulation performance is discussed and analyzed. The monolithic integration and waveguide embedding methods are introduced separately, and the characteristics of different forms of terahertz-guided wave phase modulation are also discussed. Finally, the development trends of terahertz phase modulators, possible new methods, and future application requirements are discussed.

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Ye, Longfang, Kouxiang Yuan, Chunhui Zhu, Yao Zhang, Yong Zhang, and Kunzhong Lai. "Broadband high-efficiency near-infrared graphene phase modulators enabled by metal–nanoribbon integrated hybrid plasmonic waveguides." Nanophotonics 11, no. 3 (December 21, 2021): 613–23. http://dx.doi.org/10.1515/nanoph-2021-0709.

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Abstract The phase modulator is a key component in optical communications for its phase modulation functions. In this paper, we numerically demonstrate a variety of ultra-compact high-efficiency graphene phase modulators (GPMs) based on metal–nanoribbon integrated hybrid plasmonic waveguides in the near-infrared region. Benefiting from the good in-plane mode polarization matching and strong hybrid surface plasmon polariton and graphene interaction, the 20 μm-length GPM can achieve excellent phase modulation performance with a good phase and amplitude decoupling effect, a low insertion loss around 0.3 dB/μm, a high modulation efficiency with V π L π of 118.67 V μm at 1.55 μm, which is 1–3 orders improvement compared to the state-of-the-art graphene modulators. Furthermore, it has a wide modulation bandwidth of 67.96 GHz, a low energy consumption of 157.49 fJ/bit, and a wide operating wavelength ranging from 1.3 to 1.8 μm. By reducing the overlap width of the graphene–Al2O3–graphene capacitor, the modulation bandwidth and energy consumption of the modulator can be further improved to 370.36 GHz and 30.22 fJ/bit, respectively. These compact and energy-efficient GPMs may hold a key to various high-speed telecommunications, interconnects, and other graphene-based integrated photonics applications.

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Lu, Jian-yu. "Reconstruction methods for super-resolution imaging with PSF modulation." Journal of the Acoustical Society of America 155, no. 3_Supplement (March 1, 2024): A54. http://dx.doi.org/10.1121/10.0026777.

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Recently, a super-resolution imaging method called the PSF (point spread function) modulation method was developed (Lu, IEEE TUFFC 2024). In this method, the amplitude, phase, or both of the PSF of a linear shift-invariant (LSI) imaging system is modulated so that the modulated PSF has a higher spatial frequency than that of the original PSF to reconstruct super-resolution images. The modulator can be produced and manipulated remotely by methods such as radiation force or it can be a physical particle such as micro- or nano-particle manipulated by an external force such as electrical and electromagnetic force. In principle, the super-resolution imaging method can be applied to any LSI imaging system, such as ultrasound, optical, photoacoustic, electromagnetic, underwater, nondestructive evaluation (NDE), and magnetic resonance imaging (MRI) system. These include pulse-echo ultrasound imaging, transmission imaging, wave source/field imaging, acoustical camera, and optical bright-field microscope. To optimize the quality of the images, methods for the reconstruction of pulse-echo and wave source/field super-resolution images are studied and the results will be presented. These methods include the uses of an analytic envelope of radio-frequency (RF) signals with and without windowing, “I” (in-phase) and “Q” (quadrature) signals, and the DC (direct current) component removal.

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Feng, Song, Lian-bi Li, and Bin Xue. "Research on a Micro-Nano Si/SiGe/Si Double Heterojunction Electro-Optic Modulation Structure." Advances in Condensed Matter Physics 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/8297650.

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The electro-optic modulator is a very important device in silicon photonics, which is responsible for the conversion of optical signals and electrical signals. For the electro-optic modulator, the carrier density of waveguide region is one of the key parameters. The traditional method of increasing carrier density is to increase the external modulation voltage, but this way will increase the modulation loss and also is not conducive to photonics integration. This paper presents a micro-nano Si/SiGe/Si double heterojunction electro-optic modulation structure. Based on the band theory of single heterojunction, the barrier heights are quantitatively calculated, and the carrier concentrations of heterojunction barrier are analyzed. The band and carrier injection characteristics of the double heterostructure structure are simulated, respectively, and the correctness of the theoretical analysis is demonstrated. The micro-nano Si/SiGe/Si double heterojunction electro-optic modulation is designed and tested, and comparison of testing results between the micro-nano Si/SiGe/Si double heterojunction micro-ring electro-optic modulation and the micro-nano Silicon-On-Insulator (SOI) micro-ring electro-optic modulation, Free Spectrum Range, 3 dB Bandwidth, Q value, extinction ratio, and other parameters of the micro-nano Si/SiGe/Si double heterojunction micro-ring electro-optic modulation are better than others, and the modulation voltage and the modulation loss are lower.

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Liu, Baoju, Shao Qi, Haifeng Hu, Zejun Sun, Shiming Qin, Peng Yu, and Dongfei Wang. "A Novel Frequency Double Vector Millimeter Wave Signal Generation Scheme Based on a Single Polarization Modulator With Precoding." Journal of Nanoelectronics and Optoelectronics 17, no. 9 (September 1, 2022): 1256–60. http://dx.doi.org/10.1166/jno.2022.3307.

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In the work, we employed a single polarization modulator to achieve double frequency vector millimeter wave (mm-wave) signal generation scheme with optical carrier suppression (OCS), which just depend on a polarization modulator and two linear polarizers, and electronic circuits is needless to control the drift of modulator bias points and no optical filters is needed to filter out undesirable harmonics. In this scheme, we set up a simulation platform to generate 40 GHz QPSK modulated vector millimeter-wave signals and analyzed the performance. The results showed when the input power for the generated 10-Gbit/s vector millimeter-wave into PD is not less than −23 dBm, the bit-error ratio could be below 3.8×10−3, which demonstrated that the generated vector millimeter-wave signal enabled by our proposed scheme could work well.

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Zhu, Yu-Lin, Bei-Lei Wu, Jing Li, Mu-Guang Wang, Shi-Ying Xiao, and Feng-Ping Yan. "Switchable instantaneous frequency measurement by optical power monitoring based on DP-QPSK modulator." Chinese Physics B 31, no. 4 (April 1, 2022): 044202. http://dx.doi.org/10.1088/1674-1056/ac40ff.

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We propose and analyze an instantaneous frequency measurement system by using optical power monitoring technique with improved resolution. The primary component adopted in the proposal is a dual-polarization quadrature phase shift keying (DP-QPSK) modulator which is used to modulate the microwave signal that has a designed time delay and phase shifting. The generated optical signal is sent to polarization beam splitter (PBS) in DP-QPSK modulator. Owing to the complementary transmission nature of polarization interference introduced by PBS, the frequency information is converted into the optical power and the relationship between the amplitude comparison function (ACF) and microwave frequency to be measured is established. Thus, the frequency of the microwave signal can be easily measured through monitoring the optical powers of the two output ports of the PBS. Furthermore, by adjusting the direct current (DC) biases of the DP-QPSK modulator instead of changing the electrical delay, the measurement range and resolution can be switched. In this paper, the basic principle of the instantaneous frequency measurement system is derived in detail, and simulation has been performed to investigate the resolution, the measurement range, and the influence of imperfection devices. The proposed scheme is wavelength-independent and its measurement range is switchable, which can avoid the laser wavelength drifting problem and thus greatly increasing the system flexibility.

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Oulachgar, Hassane, Martin Bolduc, Gregory Chauve, Yan Desroches, Patrick Beaupre, Jean Bouchard, and Pierre Galarneau. "Fabrication and Electro-Optical Characterization of a Nanocellulose-Based Spatial Light Modulator." MRS Advances 1, no. 10 (December 28, 2015): 631–37. http://dx.doi.org/10.1557/adv.2015.34.

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ABSTRACTNanocrystalline cellulose (NCC) is an emerging renewable nanomaterial that is promising for many diverse applications. As a renewable material, NCC and its derivatives have been widely studied, focusing on their biological, chemical, as well as mechanical properties. The electro-optical properties of NCC, however, remain relatively under explored. Birefringence is one of the important properties that make the NCC very attractive for photonic applications. The rode-like NCC fibers dispersed in certain solutions exhibit a specific preferred orientation which depends on their electrical charge, physical dimensions and the type of solutions used to disperse NCC fibers. In a recent study of Kerr-effect in functionalized NCC solutions, we demonstrated that it is possible to control the orientation of NCC fibers under an applied electric field. NCC-based spatial light modulator devices were fabricated and characterized. Results showed that the transmittance of the device can be controlled through frequency modulation of the applied electric field. In this paper we present the fabrication and electro-optical characterization of the device and discuss the relevant properties of NCC and future approaches to optimize and improve their characteristics and performance.

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Modulators, Power. "2008 IEEE International Power Modulator Conference - Power Modulators." IEEE Electrical Insulation Magazine 23, no. 5 (September 2007): 51. http://dx.doi.org/10.1109/mei.2007.4318281.

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D'Hose, C., E. Cassan, J. Baggio, O. Musseau, and J. L. Leray. "Electrical and optical response of a Mach-Zehnder electrooptical modulator to pulsed irradiation." IEEE Transactions on Nuclear Science 45, no. 3 (June 1998): 1524–30. http://dx.doi.org/10.1109/23.685234.

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Watson, M. D., P. R. Ashley, A. J. Guenthner, and M. A. G. Abushagur. "Modeling of electrooptic polymer electrical characteristics in a three-layer optical waveguide modulator." IEEE Journal of Quantum Electronics 41, no. 4 (April 2005): 589–95. http://dx.doi.org/10.1109/jqe.2005.843607.

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Journal articles on the topic 'Electrical-optical modulator'

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