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Journal articles on the topic 'Q modulator'

Author: Grafiati

Published: 8 June 2022

Last updated: 9 June 2022

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1

Yang, Zhixian, Kun Qu, and Xiang Liu. "Frequency-Octupling Millimeter-Wave Optical Vector Signal Generation via an I/Q Modulator-Based Sagnac Loop." Symmetry 11, no. 1 (January 14, 2019): 84. http://dx.doi.org/10.3390/sym11010084.

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A new method for generating frequency-octupling millimeter-wave (mm-wave) vector signals in optical fields via a Sagnac loop is proposed. In this scheme, two orthogonally polarized fourth order sidebands can be obtained through an integrated dual-polarization quadrature phase shift keying (DP-QPSK) modulator. The two optical sidebands are sent into an I/Q modulator-based Sagnac loop. The I/Q modulator is modulated by a 16QAM baseband signal. In the Sagnac loop, one of the sidebands is modulated by the baseband vector signal along one direction, and the other sideband is unmodulated along the opposite direction because the I/Q modulator has the traveling-wave nature. Thanks to this modulation property and the symmetrical structure of the Sagnac loop, a frequency-octupling mm-wave vector signal that is free from interband beating and fiber chromatic dispersion interference can be generated by the photodetector (PD). After simulating a 20 km single-mode fiber (SMF) transmission, the generated frequency-octupling vector signal was good in function.

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2

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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3

Cohen, D. A., M. Hossein-Zadeh, and A. F. J. Levi. "High-Q microphotonic electro-optic modulator." Solid-State Electronics 45, no. 9 (September 2001): 1577–89. http://dx.doi.org/10.1016/s0038-1101(01)00165-4.

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4

Alavi, M. S., R. B. Staszewski, L. C. N. de Vreede, A. Visweswaran, and J. R. Long. "All-Digital RF $I/Q$ Modulator." IEEE Transactions on Microwave Theory and Techniques 60, no. 11 (November 2012): 3513–26. http://dx.doi.org/10.1109/tmtt.2012.2211612.

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5

Kedia, Deepak, and Monika Nehra. "Extended Reach 10 Gb/s Transmission with an Optical I/Q Modulator Using VCSELs over OFDM-Based Multimode Fiber Link." International Journal of Optics 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/2395495.

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This paper investigates the possibilities of extending the reach of a 10 Gb/s orthogonal frequency division multiplexing- (OFDM-) based multimode fiber (MMF) link with an optical I/Q modulation technique through vertical cavity surface emitting lasers (VCSELs). The proposed I/Q modulation technique comprises two VCSELs in a 90° hybrid combination to produce I/Q modulated OFDM signal. The results show the excellent performance (in terms of BER and Q factor) of the direct-detection optical- (DDO-) OFDM system with the proposed I/Q modulation in comparison to the direct modulation case. The proposed system is able to achieve worst-case BER of about 1.8616 × 10−3 and Q factor of about 10.9949 dB over a 5 km MMF link. The I/Q modulation technique in the DDO-OFDM system has further been investigated for extending the transmission reach of the MMF link using multispan configuration.

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6

Hayrapetyan, Yegisabet Hakob, and Stepan Karen Petrosyan. "Construction Features of The High-Precision Laser Rangefinder Light Modulator." Journal of Architectural and Engineering Research 1, no. 1 (June 25, 2021): 26–31. http://dx.doi.org/10.54338/27382656-2021.1-5.

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The issues related to the development of a light modulator operating on the electro-optical effect of laser rangefinders by the modulation method are considered. To reduce the modulation power, it is proposed to lower the modulation frequency to 750-800 MHz, while simultaneously increasing the modulation quality to Q = 1000. The study of the phase determination error of a high-precision laser rangefinder depending on temperature showed that it is rational to construct the light modulator by radial installation of the KDP electro-optical crystal, with separated modulation and demodulation channels, while on combined resonators.

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7

Sorger, Volker J., Norberto D. Lanzillotti-Kimura, Ren-Min Ma, and Xiang Zhang. "Ultra-compact silicon nanophotonic modulator with broadband response." Nanophotonics 1, no. 1 (July 1, 2012): 17–22. http://dx.doi.org/10.1515/nanoph-2012-0009.

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AbstractElectro-optic modulators have been identified as the key drivers for optical communication and signal processing. With an ongoing miniaturization of photonic circuitries, an outstanding aim is to demonstrate an on-chip, ultra-compact, electro-optic modulator without sacrificing bandwidth and modulation strength. While silicon-based electro-optic modulators have been demonstrated, they require large device footprints of the order of millimeters as a result of weak non-linear electro-optical properties. The modulation strength can be increased by deploying a high-Q resonator, however with the trade-off of significantly sacrificing bandwidth. Furthermore, design challenges and temperature tuning limit the deployment of such resonance-based modulators. Recently, novel materials like graphene have been investigated for electro-optic modulation applications with a 0.1 dB per micrometer modulation strength, while showing an improvement over pure silicon devices, this design still requires device lengths of tens of micrometers due to the inefficient overlap between the thin graphene layer, and the optical mode of the silicon waveguide. Here we experimentally demonstrate an ultra-compact, silicon-based, electro-optic modulator with a record-high 1 dB per micrometer extinction ratio over a wide bandwidth range of 1 μm in ambient conditions. The device is based on a plasmonic metal-oxide-semiconductor (MOS) waveguide, which efficiently concentrates the optical modes’ electric field into a nanometer thin region comprised of an absorption coefficient-tuneable indium-tin-oxide (ITO) layer. The modulation mechanism originates from electrically changing the free carrier concentration of the ITO layer which dramatically increases the loss of this MOS mode. The seamless integration of such a strong optical beam modulation into an existing silicon-on-insulator platform bears significant potential towards broadband, compact and efficient communication links and circuits.

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8

Wang, Dong-Fei, Li-Ting Shan, and Lei Wang. "Photonic Filter-Free Scheme for D-Band mm-Wave Signal Generation with Frequency 12-Tupling Only via One Integrated In-Phase and Quadrature Modulator." Journal of Nanoelectronics and Optoelectronics 17, no. 1 (January 1, 2022): 40–47. http://dx.doi.org/10.1166/jno.2022.3167.

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In this work, we have proposed a new scheme of generating continuously tunable and filter-less D-band millimeter-wave (mm-wave) signal with frequency 12-tupling only via one integrated in-phase and quadrature (I/Q) modulator. The two sub-MZMs in the I/Q modulator, biased at peak point, are applied to eliminate odd order optical tones. By controlling the phase and amplitude of RF driving signals, I/Q modulator bias point, and the optical phase shifter embed in the lower arm of I/Q modulator, a frequency 12-tupling signal can be obtained through the beat frequency in the photodetector. Employing 10 GHz RF drive signal, 120 GHz millimeter wave signal can be realized by detailed mathematical formula derivation and simulation, and optical sideband suppression ratio (OSSR) can reach 37.65 dB and radio frequency sideband suppression ratio (RFSSR) can reach 32.08 dB.

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9

Nehra, Monika, and Deepak Kedia. "Design of Optical I/Q Modulator Using Dual-drive Mach-Zehnder Modulators in Coherent Optical-OFDM System." Journal of Optical Communications 39, no. 2 (April 25, 2018): 155–59. http://dx.doi.org/10.1515/joc-2016-0089.

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AbstractA CO-OFDM system combines the advantages of both coherent detection and OFDM modulation for future high speed fiber transmission. In this paper, we propose an I/Q modulation technique using dual-drive MZMs for high rate 10 Gb/s CO-OFDM system. The proposed modulator provides 10.63 dBm improved optical spectra compared to a single dual-drive MZM. The simulation results in terms of BER and Q factor are quite satisfactory upto a transmission reach of 3,000 km and that to without making use of any dispersion compensation. A BER of about 8.03×10−10and 15.06 dB Q factor have been achieved at −10.43 dBm received optical power.

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10

Blas, J. M., and J. I. Alonso. "Low cost wideband I-Q vector modulator." Electronics Letters 33, no. 1 (1997): 18. http://dx.doi.org/10.1049/el:19970031.

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11

Schmalz, Klaus, Eckard Grass, Frank Herzel, and Maxim Piz. "An Integrated 5 GHz Wideband Quadrature Modem for OFDM Gbit/s Transmission in SiGe:C BiCMOS." International Journal of Microwave Science and Technology 2007 (October 1, 2007): 1–8. http://dx.doi.org/10.1155/2007/47927.

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This paper presents a 5 GHz wideband I/Q modulator/demodulator for 650 MHz OFDM signal bandwidth, which is integrated with a 5 GHz phase locked loop for I/Q generation. The quadrature signals are derived from a 10 GHz CMOS VCO followed by a bipolar frequency divider. The phase noise at 1 MHz offset is −112 dBc/Hz for the modulator as well as for the demodulator. The chips were produced in a 0.25 μm SiGe BiCMOS technology. The signal-to-noise ratio (SNR) of transmitted/received OFDM signal and the corresponding I/Q mismatch versus baseband frequency are given. The modulator achieves an SNR of 22–23 dB, and the demodulator realizes an SNR up to 22 dB. The modulator reaches a data rate of 2.16 Gbit/s using 64 QAM OFDM, and the demodulator realizes 1.92 Gbits/s.

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12

Yi, Minwoo, Sungjun Yoo, Youngseok Bae, Sunghoon Jang, Joonhyung Ryoo, and Jinwoo Shin. "Design and Manufacture of Traveling-wave Electro-optic Modulator for X-band LFM Signal Generation." Journal of the Korea Institute of Military Science and Technology 24, no. 6 (December 5, 2021): 610–18. http://dx.doi.org/10.9766/kimst.2021.24.6.610.

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In this paper, a photonic-based microwave system technology is described, and a traveling-wave electro-optic modulator is designed and manufactured as a key component. The fabricated modulator is composed of a metal diffusion waveguide for optical transmission and a planar waveguide electrode on lithium niobate substrate for microwave transmission. The electro-optic response bandwidth of I and Q channels in a fabricated dual parallel Mach-Zehnder modulator were measured for 27.67 and 28.11 GHz, respectively. Photonic four times up-converted X-band frequency and linear frequency modulated signal were confirmed using the fabricated electro-optic modulator by S-band input signal. The confirmed broadband signal can be applied to a microwave system for surveillance and high-resolution ISAR imaging.

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13

Escalante-Zarate, Luis, Yuri O. Barmenkov, José L. Cruz, and Miguel V. Andres. "Q-Switch Modulator as a Pulse Shaper in Q-Switched Fiber Lasers." IEEE Photonics Technology Letters 24, no. 4 (February 2012): 312–14. http://dx.doi.org/10.1109/lpt.2011.2178822.

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14

Linz, A., and A. Hendrickson. "Efficient implementation of an I-Q GMSK modulator." IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing 43, no. 1 (1996): 14–23. http://dx.doi.org/10.1109/82.481470.

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15

Epel, Boris, Subramanian V. Sundramoorthy, and Howard J. Halpern. "250 MHz passive Q-modulator for reflection resonators." Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering 47B, no. 2 (April 2017): e21356. http://dx.doi.org/10.1002/cmr.b.21356.

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16

Huang, Zhiyong, Guidong Liu, and Lingling Wang. "Active modulation of quasi-bound state in the continuum based on bulk Dirac semimetals metamaterial." Applied Physics Express 15, no. 3 (February 25, 2022): 032006. http://dx.doi.org/10.35848/1882-0786/ac55e9.

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Abstract In this paper, we propose a bulk Dirac semimetals (BDSs) metamaterial to realize quasi-bound state in the continuum (quasi-BIC) based optical modulator. When perturbation is introduced into the system by breaking symmetry, the BIC will transform into quasi-BIC with high quality (Q) factor and radiation loss can be effectively controlled. What’s even more interesting is that the transmission of the quasi-BIC can be modulated by varying the Fermi energy of BDSs while the resonance frequency almost unchanged, the maximum transmission difference is up to 82% indicating that the proposed BDSs metamaterial shows good performance as an optical modulator.

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17

Anttila, Lauri, Peter Händel, Olli Mylläri, and Mikko Valkama. "Recursive learning-based joint digital predistorter for power amplifier and I/Q modulator impairments." International Journal of Microwave and Wireless Technologies 2, no. 2 (April 2010): 173–82. http://dx.doi.org/10.1017/s1759078710000280.

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The main implementation impairments degrading the performance of direct-conversion radio transmitters are in-phase/quadrature (I/Q) mismatch, local oscillator (LO) leakage, and power amplifier (PA) nonlinear distortion. In this article, we propose a recursive least-squares-based learning algorithm for joint digital predistortion (PD) of frequency-dependent PA and I/Q modulator impairments. The predistorter is composed of a parallel connection of two parallel Hammerstein (PH) predistorters and an LO leakage compensator, yielding a predistorter which as a whole is fully linear in the parameters. In the parameter estimation stage, proper feedback signal from the transmitter radio frequency (RF) stage back to the digital parts is deployed, combined with the indirect learning architecture and recursive least-squares training. The proposed structure is one of the first techniques to explicitly consider the joint estimation and mitigation of frequency-dependent PA and I/Q modulator impairments. Extensive simulation and measurement analysis is carried out to verify the operation and efficiency of the proposed PD technique. In general, the obtained results demonstrate linearization and I/Q modulator calibration performance clearly exceeding the performance of current state-of-the-art reference techniques.

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18

Shabir, Sehrish. "Comparison of RZ and NRZ Modulation Techniques by Varying Duty Cycle and Mach Zehnder Modulator." International Journal for Research in Applied Science and Engineering Technology 9, no. 11 (November 30, 2021): 1724–31. http://dx.doi.org/10.22214/ijraset.2021.39050.

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Abstract: The aim of the research being undertaken is to examine the performance of advanced modulation formats such as RD and NRZ modulation schemes and their long-haul repeater-free fibre-traffic (SMF). Modular transmission of signals by SMF has been highly attracted by several benefits, such as high chromatic dispersion tolerance (CD), simplicity of deployment and higher spectrum efficiencies. These are the essential performance indicators of an optimal modulation technique for the creation of multiplexed (DWDM) transmission networks of the future generation of dense wavelengths. Based on a comparison of the two modulation approaches I give my findings. To mimic both modulation schemes, OptiSystem software is employed. Eye diagram with measurement of the Q factor and BER is generated. Keywords: Return to Zero, Non-Return to Zero, Eye Diagram, Bandwidth, BER, Q factor.

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19

Gao, S., and R. Hui. "Frequency-modulated continuous-wave lidar using I/Q modulator for simplified heterodyne detection." Optics Letters 37, no. 11 (May 30, 2012): 2022. http://dx.doi.org/10.1364/ol.37.002022.

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20

Gupta, Arpit K., Joohwa Kim, Peter Asbeck, and James F. Buckwalter. "A 9 mW, Q-Band Direct-Conversion I/Q Modulator in SiGe BiCMOS Process." IEEE Microwave and Wireless Components Letters 22, no. 6 (June 2012): 327–29. http://dx.doi.org/10.1109/lmwc.2012.2197379.

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21

Zhang, Min, Jun Xu, and Xin Kai Cheng. "A 34 to 36 GHz Vector Modulator for Reflected Power Canceller Techniques in LFMCW Radar." Applied Mechanics and Materials 40-41 (November 2010): 283–86. http://dx.doi.org/10.4028/www.scientific.net/amm.40-41.283.

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In this paper, a 34 to 36 GHz vector modulator for using in low cost and high performance RPC (Reflected Power Canceller) is presented. The key circuit consists of two push-pull (bi-phase) attenuators arranged in phase quadrature and a 3dB quadrature coupler (branch line couplers but not Lange couplers which is different from traditional circuits in Ka band) and a Wilkinson combiner, and then transition from micro-strip to waveguide using antipodal finline. To fully exploit this circuit’s capacity to generate accurate constellations at millimeter-wave frequencies, a generalized theoretical analysis of the (push-pull) vector modulator is presented. Based on the theoretical model and the measured results, the I-Q (push-pull) vector modulator promises to be a vital component for the realization of reflected power canceller in LFMCW (Linear Frequency Modulated Continuous Wave) radar.

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22

Capmany, J., J. Mora, B. Ortega, and D. Pastor. "High-Q microwave photonic filter with a tuned modulator." Optics Letters 30, no. 17 (September 1, 2005): 2299. http://dx.doi.org/10.1364/ol.30.002299.

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23

Mok, C., M. Weel, E. Rotberg, and A. Kumarakrishnan. "Design and construction of an efficient electro-optic modulator for laser spectroscopy." Canadian Journal of Physics 84, no. 9 (September 1, 2006): 775–86. http://dx.doi.org/10.1139/p06-074.

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We discuss design considerations and construction of a home-built electro-optic phase modulator (EOM) that can be used for locking a laser to an atomic transition. The EOM is designed to operate at a resonant frequency of ≈20 MHz and imposes a phase modulation on a laser beam. The phase-modulated light is sent through a reference cell containing a dilute gas of rubidium atoms. When the laser is scanned over an atomic resonance, the absorption of light through the cell can be detected and mixed down to DC to produce a dispersion shaped “error” signal. The error signal can be used to lock the laser to the atomic resonance. We also describe tests of the basic properties of the resonant circuit. The Q of the circuit is measured to be 10, resulting in 60% efficiency for the first-order sidebands at RF drive powers of 0.7 W. Applications include the spectroscopy of laser-cooled atoms.PACS Nos.: 01.50.Pa, 39.25.+k 32.80.Pj, 42.62.Fi

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24

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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25

Hammadi, Ali, Ali Al-Askery, and Entidhar Zghair. "Quality Factor and SNR Compensation of Free Space Optical Communication Link Using Different Modulators." International Journal of Engineering & Technology 7, no. 4 (November 30, 2018): 3747. http://dx.doi.org/10.14419/ijet.v7i4.19109.

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Free space optical (FSO) systems introduce the best solution for the broadband network requirements with a cost reduction compared to the optical wire communication systems. This paper studies the signal to noise ratio (SNR) and quality factor (Q-factor) for using two types of modulation formats and compares their performance. The analysis are performed for Mach-Zehnder modulator (MZM) and electro-absorption modulator (EAM) with distance range (1-4) km of FSO by using avalanche photo-diodes (APD) receivers. The simulation results are obtained based on the Optisystem 7.0 with optical high data rate of 10 Gbs for this communication system. The simulation results have shown that MZM gives better performance compared to EAM for different ranges and for the selected beam divergence value.

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26

Zhang, Qin, and Zhi Bin Zeng. "Simulation Analysis on DPD Performance with DC Offset." Applied Mechanics and Materials 380-384 (August 2013): 4108–11. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.4108.

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DC offset of the input analog signal I and Q of quadrature modulator which is as DAC and RF channel interface will affect bit error rate (BER) of the system, the quality of the emission signals and the overall effect of DPD[. This paper focuses on the influences of non-ideal characteristics quadradure modulator on DPD technology.

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27

Chattopadhyay, Diptangshu, and Manisha Bharti. "Implementation of C-PolSK Modulation in FSO Network and Analysis of its Atmospheric Performance." Journal of Telecommunications and Information Technology 4, no. 2019 (December 30, 2019): 43–49. http://dx.doi.org/10.26636/jtit.2019.136619.

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Free Space Optical (FSO) communication is a quickly developing technology that is designed to handle high data rates while maintaining a good quality factor (Q-factor). Many novel techniques have been implemented to cope with atmospheric attenuating factors, such as fog and rain. Here, we have introduced circular polarization shift keying (C-PolSK) modulation to produce a stable and uniform light beam. The plane of polarized light keeps rotating along with the propagation vector, which helps reduce phase variations and cross-channel eﬀects. C-PolSK provides higher penetrating power and attenuation resistance over linear polarization shift keying (L-PolSK). Two diﬀerent C-PolSK models have been proposed and graphical comparisons, relying on such parameters as Q-factor, transmission distance and inputoutput power, have been made. The cases of moderate fog and rain attenuation are taken to verify the model’s eﬃciency. Polarized light is split into two orthogonal components and then modulated using the Mach-Zehnder modulator. One of the models also employs the principle of orthogonal diﬀerential phase shifting. Eye diagrams have been provided to verify the bit error rate (BER). The orthogonal diﬀerential phase shifted C-PolSK model proves to be the most suitable implementation prototype.

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28

Gao, Yongsheng, Aijun Wen, Wei Jiang, Yangyu Fan, Deyun Zhou, and You He. "Wideband Photonic Microwave SSB Up-Converter and I/Q Modulator." Journal of Lightwave Technology 35, no. 18 (September 15, 2017): 4023–32. http://dx.doi.org/10.1109/jlt.2017.2726532.

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29

Wang, Yalin, and Yongjun Yang. "Modeling and Analysis of a Closed-Loop System for High-Q MEMS Accelerometer Sensor." MATEC Web of Conferences 160 (2018): 05008. http://dx.doi.org/10.1051/matecconf/201816005008.

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High-Q sensing element is desirable for high performance while makes the loop control a great challenge. This paper presents a closed-loop system for high-Q capacitive MEMS accelerometer which has achieved loop control effectively. The proportional-derivative(PD)control is developed in the system to improve the system stability. In addition, pulse width modulation (PWM) electrostatic force feedback is designed in the loop to overcome the nonlinearity. Furthermore, a sigma-delta (ΣΔ) modulator with noise shaping is built to realize digital output. System model is built in Matlab/Simulink. The simulation results indicate that equivalent Q value is reduced to 1.5 to ensure stability and responsiveness of the system. The effective number of bits of system output is 14.7 bits. The system nonlinearity is less than 5‰. The equivalent linear model including main noise factors is built, and then a complete theory of noise and linearity analysis is established to contribute to common MEMS accelerometer research.

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30

M. A. Eid, Mahmoud, Ashraf S. Seliem, Ahmed Nabih Zaki Rashed, Abd El-Naser A. Mohammed, Mohamed Yassin Ali, and Shaimaa S. Abaza. "Duobinary modulation/predistortion techniques effects on high bit rate radio over fiber systems." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 2 (February 1, 2021): 978. http://dx.doi.org/10.11591/ijeecs.v21.i2.pp978-986.

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<span>The work has presented duobinary modulation and predistortion techniques for the radio over fiber system enhancement for achieving security level. Duobinary modulation technique has more compact modulated spectral linewidth with standard non return to zero modulation code. Different NRZ/RZ rectangle shape employed that are namely exponential rectangle shape (ERS), and Gaussian rectangle shape (GRS) for different transmission bit rates. Switching bias voltage, and switching RF voltage based LiNbO<sub>3</sub> modulator are changed to measure the performance parameters of the radio over fiber (RoF) system. Predistortion technique improves the linearity of transmitter amplifiers and it is considered as a power efficiency technique. The optimum values of the Q-factor, data error rate (BER), electrical power, signal gain, noise figure, and light signal/noise ratio are achieved with 8 Volt for both switching biases/switching RF signal at 100 GHz. Signal quality/BER and electrical power after the receiver enhancement ratio by using this technique at different RF signal frequencies. </span>

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31

Chen, Tenghui, Weichao Yao, Hiyori Uehara, Chunyang Ma, Muhammad Sohail, Chunxiang Zhang, Yanqi Ge, Dianyuan Fan, and Jun Liu. "High-peak-power and wavelength tunable acousto-optic Q-switched Er:ZBLAN fiber laser." Japanese Journal of Applied Physics 61, no. 4 (March 17, 2022): 040902. http://dx.doi.org/10.35848/1347-4065/ac58d5.

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Abstract We demonstrate Q-switching operation of a single-moded mid-infraredEr3+-doped ZBLAN (Er:ZBLAN) fiber laser based on an acousto-optic modulator. The fiber laser can produce steady Q-switched pulses as short as 24.8 ns at an average output power of 45.7 mW with a single transverse mode, corresponding to a peak power of 18.4 kW. In addition, a wavelength tuning range from 2715.4 to 2790.4 nm is also achieved in the Q-switching regime at the repetition rate of 1 kHz. The experimental results demonstrate the huge potential of producing mid-infrared energetic and wavelength tunable short-pulses in an actively Q-switched Er:ZBLAN fiber laser.

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32

Zhang, Zijian, Guowei Chen, Mingyu Yang, Yunyao Ou, Luqi Luo, Dongqin Lu, Enze Zhang, et al. "Resonance-enhanced all-optical modulation of WSe2-based micro-resonator." Nanophotonics 9, no. 8 (December 9, 2019): 2387–96. http://dx.doi.org/10.1515/nanoph-2019-0425.

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AbstractTwo-dimensional material tungsten diselenide (WSe2) nanosheets are coated on a microfibre knot resonator (MKR) to achieve an all-optical power modulation functionality. On account of the strong absorption property of WSe2 and the resonance enhancement properties of MKR, the transmitted optical power of signal light within the WSe2-based MKR can be effectively modulated. The sensitivities of light–control–light experiments with 405- and 660-nm lasers are as high as 0.32 and 0.12 dB/mW, respectively. The sensitivities and power tuning can be enhanced by a higher resonance Q and a larger extinction ratio of MKR. In terms of the response time, the average rise and fall times are 3.5/3.7 and 3.5/4 ms with 405- and 660-nm lasers, respectively. This proposed structure is expected to achieve potential applications in all-fibre-optic–based tunable device such as optical modulator, detector, and so on.

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Zhao, Lina, Wenyu Zhang, Ye Yuan, Luyang Tong, Jingjing Liu, Jie Liu, Yangjian Cai, and Yuanmei Gao. "Mo:BiVO4 Nanoparticles-Based Optical Modulator and Its Application in a 2-μm Pulsed Laser." Nanomaterials 11, no. 12 (November 29, 2021): 3243. http://dx.doi.org/10.3390/nano11123243.

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Mo:BiVO4 nanoparticles were employed as an optical modulator in a Q-switched all-solid-state Tm:YAP laser for the first time. The nonlinear optical parameters of Mo:BiVO4 nanoparticles in the 2-μm region were characterized by measuring nonlinear transmission. Saturation intensity was 718 MW/cm2, and the modulation depth was 12.3%. A stable pulse sequence was acquired with a 70.08 kHz maximum repetition rate and an 821 ns pulse width. The maximum output average power was 153 mW, corresponding to 2.18 μJ single pulse energy and 2.67 W peak power. Although the response wavelength of Mo:BiVO4 is in visible light region, our experimental results demonstrates that a saturable absorption effect for wavelengths much longer than visible light (2 μm wavelength) is still possible due to sub-bandgap absorption. Therefore, we experimentally proved that Mo:BiVO4 nanoparticles are a great candidate for use as an optical modulator of a 2-μm pulsed laser.

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Pun, K. P., C. S. Choy, C. F. Chan, and J. E. da Franca. "An I/Q Mismatch-Free Switched-Capacitor Complex Sigma–Delta Modulator." IEEE Transactions on Circuits and Systems II: Express Briefs 51, no. 5 (May 2004): 254–56. http://dx.doi.org/10.1109/tcsii.2004.827552.

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Paramonov, V. M., and A. S. Kurkov. "Q-switched Er-doped fiber source based on electrooptical modulator application." Laser Physics 25, no. 6 (May 1, 2015): 065103. http://dx.doi.org/10.1088/1054-660x/25/6/065103.

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Lv, Qiang, Kun Xu, Yitang Dai, Yan Li, Jian Wu, and Jintong Lin. "I/Q intensity-demodulation analog photonic link based on polarization modulator." Optics Letters 36, no. 23 (November 28, 2011): 4602. http://dx.doi.org/10.1364/ol.36.004602.

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Kim, Jusung, Han-Shin Jo, Kyoung-Jae Lee, Dong-Ho Lee, Dae-Hyun Choi, and Sangkil Kim. "A Low-Complexity I/Q Imbalance Calibration Method for Quadrature Modulator." IEEE Transactions on Very Large Scale Integration (VLSI) Systems 27, no. 4 (April 2019): 974–77. http://dx.doi.org/10.1109/tvlsi.2018.2883758.

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SAN, H. "Complex Bandpass AD Modulator Architecture without I, Q-Path Crossing Layout." IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E89-A, no. 4 (April 1, 2006): 908–15. http://dx.doi.org/10.1093/ietfec/e89-a.4.908.

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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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Zhang, Cheng, Dongzhou Wang, Shengjun Huang, Jimin Yang, Jie Liu, and Jing Fang. "Nonlinear Optical Response of Gold Nanobipyramids for a Doubly Q-Switched Ho-Doped Laser at a Wavelength of 2.1 µm." Nanomaterials 11, no. 2 (February 19, 2021): 535. http://dx.doi.org/10.3390/nano11020535.

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Gold nanobipyramids (Au-NBPs) were successfully fabricated using the seed-mediated growth method. The saturable absorption performance of the Au-NBPs at a 2-μm band wavelength was characterized. Using excellent-quality, mature Ho:YLF crystals, a doubly Q-switched (DQS) laser joining an acousto-optic modulator (AOM) with an Au-NBP saturable absorber (SA) was achieved. When the modulation rate of the AOM was 1 kHz, the shortest pulse width (54 ns) was attained, corresponding to the highest peak power (3.87 kW). This was compared with a singly Q-switched laser joining an AOM with an Au-NBP SA, whereby the maximum pulse width compression ratio was 15.2 and the highest peak power enhancement factor was 541.3. Our study has shown that Au-NBPs are a potential saturable absorption nanomaterial, and the DQS laser has the benefit of compressing the pulse width and increasing the peak power at a wavelength of 2.1 μm.

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Zhao, J., K. Li, F. Kong, K. Cheng, and B. Zhao. "Diode-pumped actively Nd:Lu0.33Y0.37Gd0.3VO4 Q-switched laser with electro-optic (EO) modulator." Laser Physics 22, no. 5 (April 3, 2012): 911–13. http://dx.doi.org/10.1134/s1054660x12050374.

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Zhuo, Z., J. M. Jiang, T. Li, S. G. Li, C. X. Shan, H. B. Qin, J. Li, B. Zhao, and J. Z. Chen. "Study of LD pumped Q-switched Nd:Y0.5Lu0.5VO4 laser with acousto-optic modulator." Laser Physics 21, no. 9 (July 4, 2011): 1558–61. http://dx.doi.org/10.1134/s1054660x11150370.

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43

Zhao, S., J. Zhao, G. Li, K. Yang, Y. Sun, D. Li, J. An, J. Wang, and M. Li. "Doubly Q-switched laser with electric-optic modulator and GaAs saturable absorber." Laser Physics Letters 3, no. 10 (October 1, 2006): 471–73. http://dx.doi.org/10.1002/lapl.200610038.

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Yubing, T., T. Huiming, P. Jiying, and L. HongYi. "LD-pumped actively Q-switched Yb:YAG laser with an acoustic-optical modulator." Laser Physics 18, no. 1 (January 2008): 12–14. http://dx.doi.org/10.1134/s1054660x08010027.

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Zhao, Mingming, Wen Zhou, Li Zhao, Jiangnan Xiao, Xinying Li, Feng Zhao, and Jianjun Yu. "A New Scheme to Generate Multi-Frequency Mm-Wave Signals Based on Cascaded Phase Modulator and I/Q Modulator." IEEE Photonics Journal 11, no. 5 (October 2019): 1–8. http://dx.doi.org/10.1109/jphot.2019.2939275.

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Gao, Zhi Qiang, Jin Bao Lan, Xiao Wei Liu, and Liang Yin. "The Delta-Sigma Modulator of Fractional-N Frequency Synthesizer for Wireless Sensors Network Applications." Key Engineering Materials 609-610 (April 2014): 1014–19. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.1014.

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This paper presents a design of fractional-N frequency synthesizer with low dithering, which is fabricated in a 130nm CMOS process. A 3rd-order delta-sigma modulator is based on digital multi-stage noise shaping (MASH) structure with its second and third stage dithered by 7-bit linear feedback shift register (LFSR) was designed for the frequency synthesizer, and a long word is used for the first modulator in the MASH structure. The simulation result of the whole frequency synthesizer shows that it can output two-way I/Q signal between 2.28GHz and 2.53GHz, and its spurs are lower than-75dBc.

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Zhang, Cheng, Qianqian Hao, Yuqian Zu, Mengyu Zong, Jia Guo, Feng Zhang, Yanqi Ge, and Jie Liu. "Graphdiyne Saturable Absorber for Passively Q-Switched Ho3+-Doped Laser." Nanomaterials 10, no. 9 (September 16, 2020): 1848. http://dx.doi.org/10.3390/nano10091848.

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High-quality all-carbon nanostructure graphdiyne (GDY) saturable absorber was successfully fabricated and saturable absorption properties in the 2 μm region were characterized using a commercial mode-locked laser as a pulsed source. The fabricated GDY was first used as an optical switcher in a passively Q-switched Ho laser. Under absorbed pump power of 2.4 W, the maximum average output power and shortest pulse width were 443 mW and 1.38 µs, at a repetition rate of 29.72 kHz. The results suggest that GDY nanomaterial is a promising candidate as an optical modulator for generation of short pulses in Ho-doped lasers at 2.1 μm.

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Mansour, Marwa, Abdelhalim Zekry, Mohammed K. Ali, and Heba Shawkey. "Analysis and design of a reconfigurable wideband I/Q modulator and Ultra-Wideband I/Q demodulator for multi-standard applications." Microelectronics Journal 102 (August 2020): 104830. http://dx.doi.org/10.1016/j.mejo.2020.104830.

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Slavov, D. "Controlled two-pulse generation in Q-switch mode from a single laser using Q-modulator with frustrated total internal reflection." Applied Physics B: Lasers and Optics 73, no. 7 (November 1, 2001): 677–85. http://dx.doi.org/10.1007/s003400100682.

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Jiang, J. M., Z. Zhuo, T. Li, H. B. Qin, C. X. Shan, J. Li, B. Zhao, and J. Z. Chen. "Diode-pumped Q-switched Nd:Y0.5Lu0.5VO4 laser double-modulated with an acousto-optic modulator and Cr4+:YAG saturable absorber." Laser Physics 21, no. 8 (July 4, 2011): 1358–61. http://dx.doi.org/10.1134/s1054660x11150138.

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