Journal articles: 'Waveguide gratings'

1

Meudt, Maik, Andreas Henkel, Maximilian Buchmüller, and Patrick Görrn. "A Theoretical Description of Node-Aligned Resonant Waveguide Gratings." Optics 3, no. 1 (March 4, 2022): 60–69. http://dx.doi.org/10.3390/opt3010008.

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Waveguide gratings are used for applications such as guided-mode resonance filters and fiber-to-chip couplers. A waveguide grating typically consists of a stack of a single-mode slab waveguide and a grating. The filling factor of the grating with respect to the mode intensity profile can be altered via changing the waveguide’s refractive index. As a result, the propagation length of the mode is slightly sensitive to refractive index changes. Here, we theoretically investigate whether this sensitivity can be increased by using alternative waveguide grating geometries. Using rigorous coupled-wave analysis (RCWA), the filling factors of the modes of waveguide gratings supporting more than one mode are simulated. It is observed that both long propagation lengths and large sensitivities with respect to refractive index changes can be achieved by using the intensity nodes of higher-order modes.

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Shibayama, Jun, Junji Yamauchi, and Hisamatsu Nakano. "Analysis of Plasmonic Waveguides and Gratings Using Implicit Finite-Difference Methods." Advances in OptoElectronics 2011 (September 6, 2011): 1–6. http://dx.doi.org/10.1155/2011/287284.

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Various metal-insulator-metal- (MIM-) type plasmonic waveguides and gratings are investigated numerically. Three gratings are treated: one is formed by alternately stacking two kinds of MIM waveguides, another by periodic changes in the dielectric insulator materials of an MIM waveguide, and the other by a periodic variation of the air core width in an MIM waveguide. The dispersion property of each MIM waveguide of which the grating consists is analyzed using the implicit Yee-mesh-based beam-propagation method. It is shown that the third one has a relatively large effective index modulation of the guided mode with a simple grating structure, while maintaining a low propagation loss. Further examination is given to modifications of this grating structure. The transmission characteristics are examined using the frequency-dependent implicit locally one-dimensional FDTD method. We discuss how the modified grating structure affects the bandgap of the transmission characteristics.

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Chen, Jian, Ji-Jun Feng, Hai-Peng Liu, Wen-Bin Chen, Jia-Hao Guo, Yang Liao, Jie Shen, Xue-Feng Li, Hui-Liang Huang, and Da-Wei Zhang. "Femtosecond Laser Modification of Silica Optical Waveguides for Potential Bragg Gratings Sensing." Materials 15, no. 18 (September 7, 2022): 6220. http://dx.doi.org/10.3390/ma15186220.

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The optimum femtosecond laser direct writing of Bragg gratings on silica optical waveguides has been investigated. The silica waveguide has a 6.5 × 6.5 µm2 cross-sectional profile with a 20-µm-thick silicon dioxide cladding layer. Compared with conventional grating inscribed on fiber platforms, the silica planar waveguide circuit can realize a stable performance as well as a high-efficiency coupling with the fiber. A thin waveguide cladding layer also facilitates laser focusing with an improved spherical aberration. Different from the circular fiber core matching with the Gaussian beam profile, a 1030-nm, 400-fs, and 190-nJ laser is optimized to focus on the top surface of the square silica waveguide, and the 3rd-order Bragg gratings are inscribed successfully. A 1.5-mm long uniform Bragg gratings structure with a reflectivity of 90% at a 1548.36-nm wavelength can be obtained. Cascaded Bragg gratings with different periods are also inscribed in the planar waveguide. Different reflection wavelengths can be realized, which shows great potential for wavelength multiplexing-related applications such as optical communications or sensing.

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Gu, Yitong, Ning Wang, Haorui Shang, Fei Yu, and Lili Hu. "Investigations on Grating-Enhanced Waveguides for Wide-Angle Light Couplings." Nanomaterials 12, no. 22 (November 12, 2022): 3991. http://dx.doi.org/10.3390/nano12223991.

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As a universal physical scheme, effective light couplings to waveguides favor numerous applications. However, the low coupling efficiency at wide angles prohibits this fundamental functionality and thus lowers the performance levels of photonic systems. As previously found, the transmission gratings patterned on waveguide facets could significantly improve the large-angle-inputted efficiency to the order of 10−1. Here, we continue this study with a focus on a common scenario, i.e., a grating-modified waveguide excited by the Gaussian beam. A simplified 2D theoretical model is firstly introduced, proving that the efficiency lineshape could be well flattened by elaborately arranged diffractive gratings. For demonstration, subsequent explorations for proper grating geometries were conducted, and four structural configurations were selected for later full-wave numerical simulations. The last comparison studies showcase that the analytical method approximates the finite element method-based modelings. Both methods highlight grating-empowered coupling efficiencies, being 2.5 bigger than the counterparts of the previously reported seven-ring structure. All in all, our research provides instructions to simulate grating effects on the waveguide’s light-gathering abilities. Together with algorithm-designed coupling structures, it would be of great interest to further benefit real applications, such as bioanalytical instrumentation and quantum photon probes.

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Gao, Xiaoyu, Shengjie Cao, Yongqiu Zheng, and Jiandong Bai. "A Compact Fabry–Pérot Acoustic Sensor Based on Silicon Optical Waveguide Bragg Gratings." Photonics 10, no. 8 (July 25, 2023): 861. http://dx.doi.org/10.3390/photonics10080861.

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No membranous optical sensors have excellent development prospects in aerospace and other industrial fields due to their small size and anti-electromagnetic interference. Here, we proposed a novel Fabry–Pérot (FP) cavity acoustic sensor based on silicon optical waveguide Bragg gratings. The FP cavity consists of two Bragg gratings written on the silicon-based optical waveguide and a miniature air groove. When the sound signal acts on the miniature air groove, the sound pressure changes the density of air molecules near the waveguide grating’s evanescent field, causing variation in the air’s refractive index. This results in a shift in the reflection spectrum of the FP cavity to detect the sound signal. The effects of the grating period, grating pitch quantity, and groove depth of the FP cavity on acoustic sensing were studied. The modelling predicts that the sensing sensitivity could be 0.4 nm/Pa. Theoretically, the compact self-designed acoustic sensor can withstand temperatures above 800 °C. Therefore, it has significant potential applications in precision measurement in high-temperature and high-pressure environments.

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Casalboni, M., L. Dominici, V. Foglietti, F. Michelotti, E. Orsini, C. Palazzesi, F. Stella, and P. Prosposito. "Bragg Grating Optical Filters by UV Nanoimprinting." Journal of Nanomaterials 2012 (2012): 1–5. http://dx.doi.org/10.1155/2012/186429.

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Results on an optical waveguide filter operating in the near IR region are reported. The device consists of a hybrid sol-gel -based grating loaded waveguide, obtained through the merging of conventional photolithography and UV-nanoimprinting. Starting from submicrometric gratings, fabricated by electron beam lithography, a soft mould has been produced and the original structures were replicated onto sol-gel photosensitive films. A final photolithographic step allowed the production of grating-loaded channel waveguides. The devices were optically characterized by transmission measurements in the telecom range 1450–1590 nm. The filter extinction ratio is −11 dB and the bandwidth is 1.7 nm.

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Čehovski, Marko, Jing Becker, Ouacef Charfi, Hans-Hermann Johannes, Claas Müller, and Wolfgang Kowalsky. "Single-Mode Polymer Ridge Waveguide Integration of Organic Thin-Film Laser." Applied Sciences 10, no. 8 (April 18, 2020): 2805. http://dx.doi.org/10.3390/app10082805.

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Organic thin-film lasers (OLAS) are promising optical sources when it comes to flexibility and small-scale manufacturing. These properties are required especially for integrating organic thin-film lasers into single-mode waveguides. Optical sensors based on single-mode ridge waveguide systems, especially for Lab-on-a-chip (LoC) applications, usually need external laser sources, free-space optics, and coupling structures, which suffer from coupling losses and mechanical stabilization problems. In this paper, we report on the first successful integration of organic thin-film lasers directly into polymeric single-mode ridge waveguides forming a monolithic laser device for LoC applications. The integrated waveguide laser is achieved by three production steps: nanoimprint of Bragg gratings onto the waveguide cladding material EpoClad, UV-Lithography of the waveguide core material EpoCore, and thermal evaporation of the OLAS material Alq3:DCM2 on top of the single-mode waveguides and the Bragg grating area. Here, the laser light is analyzed out of the waveguide facet with optical spectroscopy presenting single-mode characteristics even with high pump energy densities. This kind of integrated waveguide laser is very suitable for photonic LoC applications based on intensity and interferometric sensors where single-mode operation is required.

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Soltani, Mohamadreza. "Enhancement of second harmonic generation using a novel asymmetric metal–graphene–insulator–metal plasmonic waveguide." Journal of Nonlinear Optical Physics & Materials 27, no. 01 (March 2018): 1850003. http://dx.doi.org/10.1142/s0218863518500030.

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Here, we propose a novel plasmonic structure, called asymmetric plasmonic nanocavity grating (APNCG), which is shown to dramatically enhance nonlinear optical process of second harmonic generation (SHG). The proposed structure consists of two different metals on both sides of lithium niobate and a thin layer of graphene. By using two different metals the nonlinear susceptibility of the waveguide would be increased noticeably causing to increase SHG. On the other hand, it consists of two identical gratings on one side. By two identical gratings, the pump beam is coupled to two opposing SPP waves, which interfere with each other and result in SPP standing wave in the region between the two gratings. The distance between two gratings will be optimized to reach the highest SHG. It will be shown that by optimizing the geometry of proposed structure and using different metals, field enhancement in APNCG waveguides can result in large enhancement of SHG.

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Marzouk, Ibtihel, David Riassetto, Alain Morand, Davide Bucci, and Michel Langlet. "Study and Optimization of a Micro-Structured Waveguiding and Fluorescent Sol-Gel Architecture." Molecules 28, no. 12 (June 7, 2023): 4608. http://dx.doi.org/10.3390/molecules28124608.

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Channel waveguides with diffraction gratings at their input and output for light injection and extraction, respectively, constitute the key components for applications in integrated optics and photonics. Here, we report for the first time on such fluorescent micro-structured architecture entirely elaborated on glass by sol-gel processing. This architecture particularly takes advantage of a high-refractive index and transparent titanium oxide-based, sol-gel photoresist that can be imprinted through a single photolithography step. This resist enabled us to photo-imprint the input and output gratings on a photo-imprinted channel waveguide doped with a ruthenium complex fluorophore (Rudpp). In this paper, the elaboration conditions and optical characterizations of derived architectures are presented and discussed with respect to optical simulations. We firstly show how the optimization of a two-step deposition/insolation sol-gel procedure leads to reproducible and uniform grating/waveguide architectures elaborated on rather large dimensions. Then, we show how this reproducibility and uniformity govern the reliability of fluorescence measurements in waveguiding configuration. These measurements demonstrate that: (i) our sol-gel architecture is well adapted to the efficient channel–waveguide/diffraction grating coupling at the Rudpp excitation and emission wavelengths; (ii) it enables an efficient propagation of the emission signal in the core of the waveguide allowing its photo-detection after extraction through the output grating; and (iii) it is affected by very reduced parasitic mechanisms, such as propagation losses and photobleaching features. This work constitutes a promising preliminary step toward the integration of our architecture in a microfluidic platform for further fluorescence measurements in liquid medium and waveguiding configuration.

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Missinne, Jeroen, Nuria Teigell Benéitez, Marie-Aline Mattelin, Alfredo Lamberti, Geert Luyckx, Wim Van Paepegem, and Geert Van Steenberge. "Bragg-Grating-Based Photonic Strain and Temperature Sensor Foils Realized Using Imprinting and Operating at Very Near Infrared Wavelengths." Sensors 18, no. 8 (August 18, 2018): 2717. http://dx.doi.org/10.3390/s18082717.

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Thin and flexible sensor foils are very suitable for unobtrusive integration with mechanical structures and allow monitoring for example strain and temperature while minimally interfering with the operation of those structures. Electrical strain gages have long been used for this purpose, but optical strain sensors based on Bragg gratings are gaining importance because of their improved accuracy, insusceptibility to electromagnetic interference, and multiplexing capability, thereby drastically reducing the amount of interconnection cables required. This paper reports on thin polymer sensor foils that can be used as photonic strain gage or temperature sensors, using several Bragg grating sensors multiplexed in a single polymer waveguide. Compared to commercially available optical fibers with Bragg grating sensors, our planar approach allows fabricating multiple, closely spaced sensors in well-defined directions in the same plane realizing photonic strain gage rosettes. While most of the reported Bragg grating sensors operate around a wavelength of 1550 nm, the sensors in the current paper operate around a wavelength of 850 nm, where the material losses are the lowest. This was accomplished by imprinting gratings with pitches 280 nm, 285 nm, and 290 nm at the core-cladding interface of an imprinted single mode waveguide with cross-sectional dimensions 3 × 3 µm2. We show that it is possible to realize high-quality imprinted single mode waveguides, with gratings, having only a very thin residual layer which is important to limit bend losses or cross-talk with neighboring waveguides. The strain and temperature sensitivity of the Bragg grating sensors was found to be 0.85 pm/µε and −150 pm/°C, respectively. These values correspond well with those of previously reported sensors based on the same materials but operating around 1550 nm, taking into account that sensitivity scales with the wavelength.

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Tan, Haoyang, Weijie Liu, Yuheng Zhang, Shaojie Yin, Daoxin Dai, Shiming Gao, and Xiaowei Guan. "High-Efficiency Broadband Grating Couplers for Silicon Hybrid Plasmonic Waveguides." Photonics 9, no. 8 (August 5, 2022): 550. http://dx.doi.org/10.3390/photonics9080550.

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We report the designs of on-chip grating couplers for the silicon hybrid plasmonic waveguides, which is the first proposal, to the best of our knowledge, for the direct coupling between a standard single-mode fiber and a hybrid plasmonic waveguide. By leveraging the apodized gratings and a two-stage-taper mode converter, we obtain a theoretical coupling efficiency of 79% (−1.03 dB) at the 1550 nm wavelength and a 3-dB bandwidth of 73 nm between the fiber and a 100 nm-wide silicon hybrid plasmonic waveguide with a bottom metal layer. We further propose grating couplers for three other sorts of silicon hybrid plasmonic waveguides with a metal cap and theoretically achieve good performances with coupling efficiencies larger than 47% and bandwidths larger than 51 nm. The proposed direct coupling scheme can avoid extra insertion losses and additional alignment processes that conventional indirect coupling schemes produce. It is believed to be a new step forward to the CMOS-compatible and large-scale integration based on the plasmonic waveguides.

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Schmid, J. H., P. Cheben, S. Janz, J. Lapointe, E. Post, A. Delâge, A. Densmore, B. Lamontagne, P. Waldron, and D. X. Xu. "Subwavelength Grating Structures in Silicon-on-Insulator Waveguides." Advances in Optical Technologies 2008 (July 13, 2008): 1–8. http://dx.doi.org/10.1155/2008/685489.

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First implementations of subwavelength gratings (SWGs) in silicon-on-insulator (SOI) waveguides are discussed and demonstrated by experiment and simulations. The subwavelength effect is exploited for making antireflective and highly reflective waveguide facets as well as efficient fiber-chip coupling structures. We demonstrate experimentally that by etching triangular SWGs into SOI waveguide facets, the facet power reflectivity can be reduced from 31% to <2.5%. Similar structures using square gratings can also be used to achieve high facet reflectivity. Finite difference time-domain simulations show that >94% facet reflectivity can be achieved with square SWGs for 5 μm thick SOI waveguides. Finally, SWG fiber-chip couplers for SOI photonic wire waveguides are introduced, including design, simulation, and first experimental results.

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Kefer, Stefan, Gian-Luca Roth, Julian Zettl, Bernhard Schmauss, and Ralf Hellmann. "Sapphire Photonic Crystal Waveguides with Integrated Bragg Grating Structure." Photonics 9, no. 4 (April 1, 2022): 234. http://dx.doi.org/10.3390/photonics9040234.

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This contribution demonstrates photonic crystal waveguides generated within bulk planar sapphire substrates. A femtosecond laser is used to modify the refractive index in a hexagonal pattern around the pristine waveguide core. Near-field measurements reveal single-mode behavior at a wavelength of 1550 nm and the possibility to adapt the mode-field diameter. Based on far-field examinations, the effective refractive index contrast between the pristine waveguide core and depressed cladding is estimated to 3·10−4. Additionally, Bragg gratings are generated within the waveguide core. Due to the inherent birefringence of Al2O3, the gratings exhibit two distinct wavelengths of main reflection. Each reflection peak exhibits a narrow spectral full width at a half maximum of 130 pm and can be selectively addressed by exciting the birefringent waveguide with appropriately polarized light. Furthermore, a waveguide attenuation of 1 dB cm−1 is determined.

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Hessler, Steffen, Marieke Rüth, Horst-Dieter Lemke, Bernhard Schmauss, and Ralf Hellmann. "Deep UV Formation of Long-Term Stable Optical Bragg Gratings in Epoxy Waveguides and Their Biomedical Sensing Potentials." Sensors 21, no. 11 (June 3, 2021): 3868. http://dx.doi.org/10.3390/s21113868.

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In this article, we summarize our investigations on optimized 248 nm deep ultraviolet (UV) fabrication of highly stable epoxy polymer Bragg grating sensors and their application for biomedical purposes. Employing m-line spectroscopy, deep UV photosensitivity of cross-linked EpoCore thin films in terms of responding refractive index change is determined to a maximum of Δn = + (1.8 ± 0.2) × 10−3. All-polymer waveguide Bragg gratings are fabricated by direct laser irradiation of lithographic EpoCore strip waveguides on compatible Topas 6017 substrates through standard +1/-1-order phase masks. According near-field simulations of realistic non-ideal phase masks provide insight into UV dose-dependent characteristics of the Bragg grating formation. By means of online monitoring, arising Bragg reflections during grating inscription via beforehand fiber-coupled waveguide samples, an optimum laser parameter set for well-detectable sensor reflection peaks in respect of peak strength, full width at half maximum and grating attenuation are derived. Promising blood analysis applications of optimized epoxy-based Bragg grating sensors are demonstrated in terms of bulk refractive index sensing of whole blood and selective surface refractive index sensing of human serum albumin.

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Tortschanoff, Andreas, Christian Ranacher, Cristina Consani, Gerald Stocker, Thomas Grille, and Thomas Ostermann. "Chirped Grating IR-Filter on a Waveguide for Sensing Applications." Proceedings 42, no. 1 (November 14, 2019): 81. http://dx.doi.org/10.3390/ecsa-6-06547.

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We present results for a specific filter design for silicon waveguides, which features a transmission wavelength and bandwidth well suited for carbon dioxide sensing. Simulations were performed using Comsol Multiphysics and the design was optimized for a central wavelength of 4.26 µm. Furthermore, we included real-world effects like the discrete resolution of the design grid as well as process-specific fabrication tolerances. The devised structures were based on a photonic waveguide concept, which was developed recently for evanescent-field-based sensing applications. Slab waveguides with gratings on top as well as strip waveguides with sidewall gratings were considered. The concept and design are discussed in detail in order to highlight the underlying ideas.

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Butt, Muhammad Ali. "Numerical investigation of a small footprint plasmonic Bragg grating structure with a high extinction ratio." Photonics Letters of Poland 12, no. 3 (September 30, 2020): 82. http://dx.doi.org/10.4302/plp.v12i3.1042.

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In this paper, miniaturized design of a plasmonic Bragg grating filter is investigated via the finite element method (FEM). The filter is based on a plasmonic metal-insulator-metal waveguide deposited on a quartz substrate. The corrugated Bragg grating designed for near-infrared wavelength range is structured on both sides of the waveguide. The spectral characteristics of the filter are studied by varying the geometric parameters of the filter design. As a result, the maximum ER and bandwidth of 36.2 dB and 173 nm is obtained at λBragg=976 nm with a filter footprint of as small as 1.0 x 8.75 µm2, respectively. The ER and bandwidth can be further improved by increasing the number of grating periods and the strength of the grating, respectively. Moreover, the Bragg grating structure is quite receptive to the refractive index of the medium. These features allow the employment of materials such as polymers in the metal-insulator-metal waveguide which can be externally tuned or it can be used for refractive index sensing applications. The sensitivity of the proposed Bragg grating structure can offer a sensitivity of 950 nm/RIU. We believe that the study presented in this paper provides a guideline for the realization of small footprint plasmonic Bragg grating structures which can be employed in filter and refractive index sensing applications. Full Text: PDF ReferencesJ. W. Field et al., "Miniaturised, Planar, Integrated Bragg Grating Spectrometer", 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference (CLEO/Europe-EQEC), Munich, Germany, 2019, CrossRef L. Cheng, S. Mao, Z. Li, Y. Han, H.Y. Fu, "Grating Couplers on Silicon Photonics: Design Principles, Emerging Trends and Practical Issues", Micromachines, 11, 666 (2020). CrossRef J. Missinne, N. T. Beneitez, M-A. Mattelin, A. Lamberti, G. Luyckx, W. V. Paepegem, G. V. Steenberge, "Bragg-Grating-Based Photonic Strain and Temperature Sensor Foils Realized Using Imprinting and Operating at Very Near Infrared Wavelengths", Sensors, 18, 2717 (2018). CrossRef M. A. Butt, S.N. Khonina, N.L. Kazanskiy, "Numerical analysis of a miniaturized design of a Fabry–Perot resonator based on silicon strip and slot waveguides for bio-sensing applications", Journal of Modern Optics, 66, 1172-1178 (2019). CrossRef H. Qiu, J. Jiang, P. Yu, T. Dai, J. Yang, H. Yu, X. Jiang, "Silicon band-rejection and band-pass filter based on asymmetric Bragg sidewall gratings in a multimode waveguide", Optics Letters, 41, 2450 (2016). CrossRef M. A. Butt, S.N. Khonina, N.L. Kazanskiy, "Optical elements based on silicon photonics", Computer Optics, 43, 1079-1083 (2019). CrossRef N. L. Kazanskiy, S.N. Khonina, M.A. Butt, "Plasmonic sensors based on Metal-insulator-metal waveguides for refractive index sensing applications: A brief review", Physica E, 117, 113798 (2020). CrossRef L. Lu et al, "Mode-Selective Hybrid Plasmonic Bragg Grating Reflector", IEEE Photonics Technology Letters, 22, 1765-1767 (2012). CrossRef R. Negahdari, E. Rafiee, F. Emami, "Design and simulation of a novel nano-plasmonic split-ring resonator filter", Journal of Electromagnetic Waves and Applications, 32, 1925-1938 (2018). CrossRef M. Janfaza, M. A. Mansouri-Birjandi, "Tunable plasmonic band-pass filter based on Fabry–Perot graphene nanoribbons", Applied Physics B, 123, 262 (2017). CrossRef C. Wu, G. Song, L. Yu, J.H. Xiao, "Tunable narrow band filter based on a surface plasmon polaritons Bragg grating with a metal–insulator–metal waveguide", Journal of Modern Optics, 60, 1217-1222 (2013). CrossRef J. Zhu, G. Wang, "Sense high refractive index sensitivity with bragg grating and MIM nanocavity", Results in Physics, 15, 102763 (2019). CrossRef Y. Binfeng, H. Guohua, C. Yiping, "Design of a compact and high sensitive refractive index sensor base on metal-insulator-metal plasmonic Bragg grating", Optics Express, 22, 28662-28670 (2014). CrossRef A.D. Simard, Y. Painchaud, S. Larochelle, "Small-footprint integrated Bragg gratings in SOI spiral waveguides", International Quantum Electronics Conference Lasers and Electro-Optics Europe, IEEE, Munich, Germany (2013). CrossRef C. Klitis, G. Cantarella, M. J. Strain, M. Sorel, "High-extinction-ratio TE/TM selective Bragg grating filters on silicon-on-insulator", Optics Letters, 42, 3040 (2017). CrossRef J. Ctyroky et al., "Design of narrowband Bragg spectral filters in subwavelength grating metamaterial waveguides", Optics Express, 26, 179 (2018). CrossRef M.A. Butt, N.L. Kazanskiy, S.N. Khonina, "Hybrid plasmonic waveguide race-track µ-ring resonator: Analysis of dielectric and hybrid mode for refractive index sensing applications", Laser Phys., 30, 016202 (2020). CrossRef M. A. Butt, N.L. Kazanskiy, S.N. Khonina, "Label-free detection of ambient refractive index based on plasmonic Bragg gratings embedded resonator cavity sensor", Journal of Modern Optics, 66, 1920-1925 (2019). CrossRef N. L. Kazanskiy, M.A. Butt, Photonics Letters of Poland, 12, 1-3 (2020). CrossRef Z. Guo, K. Wen, Q. Hu, W. Lai, J. Lin, Y. Fang, "Plasmonic Multichannel Refractive Index Sensor Based on Subwavelength Tangent-Ring Metal–Insulator–Metal Waveguide", Sensors, 18, 1348 (2018). CrossRef

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Gu, Yuchen, Yishi Weng, Yuning Zhang, Chuang Wang, Ran Wei, Wei Wang, Nan Lin, Lixuan Zhang, and Baoping Wang. "A Study of the Field of View Performance for Full-Color Waveguide Displays Based on Polarization Volume Gratings." Crystals 12, no. 12 (December 12, 2022): 1805. http://dx.doi.org/10.3390/cryst12121805.

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Multilayer waveguide structures can realize full-color AR displays of diffractive waveguides. This paper discusses the field-of-view characteristics of a waveguide system with a multilayer structure when polarization volume gratings (PVG) are applied as couplers to achieve a full-color display. The effects of the refractive index and period parameter of PVG-couplers on the field of view are investigated. In addition, a PVG waveguide sample with an optimized design is prepared. The experimental results show that the designed waveguide system can achieve a full-color AR display with a 45° diagonal field of view, which verifies the feasibility of the design and provides a potential solution for AR color waveguide display applications.

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Shishova, Maria, Alexander Zherdev, Sergey Odinokov, Vladimir Venediktov, Dmitrii Lushnikov, and Yohan Kim. "Selective Couplers Based on Multiplexed Volume Holographic Gratings for Waveguide Displays." Photonics 8, no. 7 (June 22, 2021): 232. http://dx.doi.org/10.3390/photonics8070232.

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Diffraction waveguides are widely used in augmented reality devices as information display systems for the introduction of data into the human visual field in order to supplement information about the world around us. This paper formulates the principles of radiation conversion in diffraction waveguides made of photo-thermo-refractive glass on the basis of multiplexed volume holographic gratings, and the advantages and disadvantages of high spectral-angular selectivity are analyzed. In the optical scheme, each of the superimposed volume holographic gratings in the diffraction waveguide forms a corresponding part of the composite angular field of view of the augmented reality device. A proposed mathematical model based on angular multiplexing made it possible to synthesize the diffraction optical element for a new type of diffraction waveguide made from photo-thermo-refractive glass and to create a prototype with an angular resolution of at least 3.0 ± 0.5′, with a brightness change in the image of less than 20% and with a composite angular field of view of 32°.

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Hsu, Fang Chang, In Chung Wu, and Chi Ting Ho. "Fabrication of a Polymeric Ridge Waveguide Filter Using a Replication Process." Applied Mechanics and Materials 321-324 (June 2013): 443–46. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.443.

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The traditional wavelength filter only have one face of grating, the gratings length must be long enough to obtain good filtering result, so the filter device can not be made to a small size. We describe a procedure for rapidly and conveniently prototyping Bragg grating on the three side of the polymer ridge waveguide using holographic interferometry and micro-molding processes. In this experiment, the master of the periodic structure was created on an i-line submicrometer positive photoresist film by a holographic interference using a He-Cd (325nm) laser. A subsequent mold using polydimethylsiloxane (PDMS) polymer was cast against this master and used as a stamp to transfer the grating pattern onto a UV cure epoxy. The technique shows accurate control for the transferring of a gratings period and depth. It can obtain the filtering result with very short grating length which means that it can be made with a small filtering device.

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Kotyczka, T., and R. Rogoziński. "Long Period Waveguide Gratings in Planar Gradient Waveguides." Acta Physica Polonica A 122, no. 5 (November 2012): 841–46. http://dx.doi.org/10.12693/aphyspola.122.841.

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Dhavamani, Vigneshwar, Srijani Chakraborty, S. Ramya, and Somesh Nandi. "Design and Simulation of Waveguide Bragg Grating based Temperature Sensor in COMSOL." Journal of Physics: Conference Series 2161, no. 1 (January 1, 2022): 012047. http://dx.doi.org/10.1088/1742-6596/2161/1/012047.

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Abstract With the advancements in the domain of photonics and optical sensors, Fibre Bragg Grating (FBG) sensors, owing to their increased advantages, have been researched widely and have proved to be useful in sensing applications. Moreover, the advent of Photonic Integrated Circuits (PICs) demands the incorporation of optical sensing in waveguides, which can be integrated on silicon photonic chips. In this paper, the design of a sub-micron range Waveguide Bragg Grating (WBG) based temperature sensor with high peak reflectivity and thermal sensitivity is proposed. The flexibility of COMSOL Multiphysics software is explored to simulate the sensor and the results are verified with the analytical values calculated using MATLAB. The simulation is carried out for the proposed design having 16000 gratings and a corresponding peak reflectivity of 0.953 is obtained. A thermal sensitivity of 80 pm/K is achieved, which is approximately eight times better than that of FBG based sensor.

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Solomashenko, Artem, Alexei Kuznetsov, Vladimir Nikolaev, and Olga Afanaseva. "Development of a Holographic Waveguide with Thermal Compensation for Augmented Reality Devices." Applied Sciences 12, no. 21 (November 7, 2022): 11281. http://dx.doi.org/10.3390/app122111281.

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In this research, studies were conducted on the possibility of providing thermal compensation of the information display device circuit based on a holographic waveguide when the wavelength of the radiation source ch as a result of changes in ambient temperature. A variant of implementing the waveguide structure in terms of the geometry of the diffraction gratings arrangement is proposed, its main parameters (grating period, thickness, refractive index) and the dependencies between them affecting the quality of the reproduced image are determined.

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Smirnova, Tatiana, Volodymyr Fitio, Oksana Sakhno, Pavel Yezhov, Andrii Bendziak, Volodymyr Hryn, and Stefano Bellucci. "Resonant and Sensing Performance of Volume Waveguide Structures Based on Polymer Nanomaterials." Nanomaterials 10, no. 11 (October 24, 2020): 2114. http://dx.doi.org/10.3390/nano10112114.

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Organic–inorganic photocurable nanocomposite materials are a topic of intensive research nowadays. The wide variety of materials and flexibility of their characteristics provide more freedom to design optical elements for light and neutron optics and holographic sensors. We propose a new strategy of nanocomposite application for fabricating resonant waveguide structures (RWS), whose working principle is based on optical waveguide resonance. Due to their resonant properties, RWS can be used as active tunable filters, refractive index (RI) sensors, near-field enhancers for spectroscopy, non-linear optics, etc. Our original photocurable organic–inorganic nanocomposite was used as a material for RWS. Unlike known waveguide structures with corrugated surfaces, we investigated the waveguide gratings with the volume modulation of the RI fabricated by a holographic method that enables large-size structures with high homogeneity. In order to produce thin photosensitive waveguide layers for their subsequent holographic structuring, a special compression method was developed. The resonant and sensing properties of new resonant structures were experimentally examined. The volume waveguide gratings demonstrate narrow resonant peaks with a bandwidth less than 0.012 nm. The Q-factor exceeds 50,000. The sensor based on waveguide volume grating provides detection of a minimal RI change of 1 × 10−4 RIU. Here we also present the new theoretical model that is used for analysis and design of developed RWS. Based on the proposed model, fairly simple analytical relationships between the parameters characterizing the sensor were obtained.

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Chiang, K. S., K. P. Lor, Q. Liu, C. K. Chow, Y. M. Chu, and H. P. Chan. "Long-Period Waveguide Gratings." Japanese Journal of Applied Physics 43, no. 8B (August 25, 2004): 5690–96. http://dx.doi.org/10.1143/jjap.43.5690.

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Kulishov, Mykola, Jacques M. Laniel, Nicolas Bélanger, José Azaña, and David V. Plant. "Nonreciprocal waveguide Bragg gratings." Optics Express 13, no. 8 (2005): 3068. http://dx.doi.org/10.1364/opex.13.003068.

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Bellucci, Stefano, Andrii Bendziak, Oleksandr Vernyhor, and Volodymyr M. Fitio. "Phenomenon of Electromagnetic Field Resonance in Metal and Dielectric Gratings and Its Possible Practical Applications." Condensed Matter 5, no. 3 (July 24, 2020): 49. http://dx.doi.org/10.3390/condmat5030049.

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Calculations of the field distribution in the structure of the dielectric substrate/buffer layer/volume phase grating/analyzed medium were performed. It is shown that in the presence of a buffer layer with a low refractive index in the dielectric waveguide leads to a shift of the maximum field at the waveguide resonance into analyzed medium. As a result, the spectral and angular sensitivity of the corresponding sensor increases. Based on the waveguide equation, analytical expressions are obtained that connect the spectral and angular sensitivity of the sensor to the sensitivity of the propagation constant change due to the refractive index change of the analyzed medium. The conditions for the excitation of the resonance of surface plasmon–polariton waves in the structure with a metal or dielectric grating on a metal substrate are also given. The fields that occur at resonance for silver and gold gratings are calculated.

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Liu, Jianping, Weilin Wang, Fang Xie, Xiaoming Zhang, Xia Zhou, Yijun Yuan, and Lingling Wang. "Excitation of Surface Plasmon Polariton Modes with Double-Layer Gratings of Graphene." Nanomaterials 12, no. 7 (March 30, 2022): 1144. http://dx.doi.org/10.3390/nano12071144.

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A long-range surface plasmon polariton (SPP) waveguide, composed of double-layer graphene, can be pivotal in transferring and handling mid-infrared electromagnetic waves. However, one of the key challenges for this type of waveguide is how to excite the SPP modes through an incident light beam. In this study, our proposed design of a novel grating, consisting of a graphene-based cylindrical long-range SPP waveguide array, successfully addresses this issue using finite-difference time-domain simulations. The results show that two types of symmetric coupling modes (SCMs) are excited through a normal incident light. The transmission characteristics of the two SCMs can be manipulated by changing the interaction of the double-layer gratings of graphene as well as by varying various parameters of the device. Similarly, four SCMs can be excited and controlled by an oblique incident light because this light source is equivalent to two orthogonal beams of light. Furthermore, this grating can be utilized in the fabrication of mid-infrared optical devices, such as filters and refractive index sensors. This grating, with double-layer graphene arrays, has the potential to excite and manipulate the mid-infrared electromagnetic waves in future photonic integrated circuits.

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Hessler, Steffen, Patrick Bott, Stefan Kefer, Bernhard Schmauss, and Ralf Hellmann. "Multipurpose Polymer Bragg Grating-Based Optomechanical Sensor Pad." Sensors 19, no. 19 (September 23, 2019): 4101. http://dx.doi.org/10.3390/s19194101.

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Flexible epoxy waveguide Bragg gratings are fabricated on a low-modulus TPX™ polymethylpentene polyolefin substrate for an easy to manufacture and low-cost optomechanical sensor pad providing exceedingly multipurpose application potentials. Rectangular EpoCore negative resist strip waveguides are formed employing standard UV mask lithography. Highly persistent Bragg gratings are inscribed directly into the channel waveguides by permanently modifying the local refractive indices through a well-defined KrF excimer laser irradiated +1/-1 order phase mask. The reproducible and vastly versatile sensing capabilities of this easy-to-apply optomechanical sensor pad are demonstrated in the form of an optical pickup for acoustic instruments, a broadband optical accelerometer, and a biomedical vital sign sensor monitoring both respiration and pulse at the same time.

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YIN, SHIZHUO. "APPLICATION OF PHOTOREFRACTIVE FIBER AND WAVEGUIDE GRATINGS TO FAST SPEED NARROW BAND TUNABLE FILTERS." Journal of Nonlinear Optical Physics & Materials 08, no. 01 (March 1999): 147–58. http://dx.doi.org/10.1142/s0218863599000102.

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In this paper, the progress of the application of photorefractive fiber and waveguide crystal gratings to a narrow band, fast speed, tunable filter is presented. This novel filter is based on tunable Bragg grating. It uses the diffraction effect of Bragg grating to select the wavelength and the electro-optic effect of the grating to tune the effective grating period. Several approaches of fabricating this type of tunable Bragg grating based filter are discussed and some preliminary results are provided. It is shown that the tuning speed of this type of filter can be in the ns range and the bandwidth can be as narrow as 0.01 nm.

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Bonnel, Morgane, Ibtihel Marzouk, David Riassetto, Alain Morand, Davide Bucci, and Michel Langlet. "Setting Up and Assessing a New Micro-Structured Waveguiding Fluorescent Architecture on Glass Entirely Elaborated by Sol–Gel Processing." Materials 15, no. 3 (January 27, 2022): 979. http://dx.doi.org/10.3390/ma15030979.

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Channel waveguides with diffraction gratings at their input and output for light injection and extraction, respectively, are extensively exploited for optical and photonic applications. In this paper, we report for the first time on such an architecture on glass entirely elaborated by sol–gel processing using a titanium-oxide-based photoresist that can be imprinted through a single photolithography step. This work is more particularly focused on a fluorescent architecture including channel waveguides doped with a ruthenium-complex fluorophore (tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II), Rudpp). The study demonstrates that this original sol–gel micro-structured architecture is well adapted to efficient channel waveguide/diffraction grating coupling and propagation of the fluorescence excitation and emission signals in the core of the channel waveguide. It demonstrates, in particular, a relatively large tolerance of several degrees in the angular injection fiber positioning and an important axial and vertical fiber spatial positioning tolerance of more than 100 µm at the Rudpp emission wavelength. The measurements also indicate that, in the conditions tested in this work, a Rudpp concentration of around 0.1 mM and a channel waveguide length of 2 to 5 mm offer the best trade-off in terms of excitation signal propagation and emission signal detection. This work constitutes a promising preliminary step toward the integration of our architecture into a microfluidic platform for fluorescence measurement in a liquid medium and waveguiding configuration.

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Chang, Shaojie, Zhenhua Wu, Diwei Liu, Luwei Liu, Min Hu, Yanyu Wei, Yubin Gong, and Shenggang Liu. "Ultra-wideband BWO with waveguide loaded grating." Journal of Physics: Conference Series 2478, no. 6 (June 1, 2023): 062037. http://dx.doi.org/10.1088/1742-6596/2478/6/062037.

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Abstract This paper presents a solution for a tunable broadband terahertz radiation source, which can be realized by a newly designed BWO (Backward Wave Oscillator) using slow-wave structure with dual waveguide-loaded gratings. Gratings in two rows of the same height operate in different frequency ranges. Additionally, the signal-to-noise ratio within the operating frequency has been dramatically improved by placing a lossy material at the end of the waveguide. The operating frequency of the double gratings alternate from 185.63 GHz to 239.6 GHz and 244.08 GHz to 291.93 GHz accordingly. Ultimately, the relative bandwidth of the whole device reaches 41.7%.

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Bellucci, Stefano, Volodymyr Fitio, Iryna Yaremchuk, Oleksandr Vernyhor, and Yaroslav Bobitski. "Features of the Resonance in a Rectangular Dielectric Surace-Relief Gratings Illuminated with a Limited Cross Section Gaussian Beam." Nanomaterials 12, no. 1 (December 28, 2021): 72. http://dx.doi.org/10.3390/nano12010072.

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In this work the features of the resonance in a rectangular dielectric surface-relief gratings, illuminated with a limited cross-section Gaussian beam, have been studied. The rigorous coupled wave method and beam decomposition into the plane waves by the Fourier transform have been used. It is shown that there is a resonant wavelength for each thickness of the dielectric grating. The value of resonant wavelength depends on the beam angle of incidence on the gratings. Moreover, the two types of resonances can occur in the grating at certain grating parameters. The power reflection coefficient is practically equal to unity for the first type of resonance and is much smaller than unity, for the second one. The obtained results extend the knowledge regarding the nature of the waveguide resonance in the dielectric grating, considering the limited cross section beam, and they can increase its use in many applications.

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Xu, D. X., W. N. Ye, S. Janz, A. Delâge, P. Cheben, B. Lamontagne, E. Post, and P. Waldron. "Stress Induced Effects for Advanced Polarization Control in Silicon Photonics Components." Advances in Optical Technologies 2008 (June 22, 2008): 1–10. http://dx.doi.org/10.1155/2008/689715.

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We review the use of the oxide cladding stress-induced photoelastic effect to modify the polarization dependent properties in silicon-on-insulator (SOI) waveguide components, and highlight characteristics particular to this high index contrast (HIC) systems. The birefringence in SOI waveguides has its origin in the electromagnetic boundary conditions at the waveguide boundaries, and can be further modified by the presence of stress in the waveguiding materials. With typical stress levels in SiO2 films, which are often used as the upper cladding, the waveguide effective index can be altered anisotropically up to the order of 10−3 for ridges with heights ranging from 1 μm to 5 μm. This effect can be used effectively to counter the waveguide geometrical birefringence, allowing the waveguide cross-section profiles to be optimized for design criteria other than null geometrical birefringence. Design strategies are developed for using stress engineering to achieve a variety of functions. Polarization insensitive arrayed waveguide gratings (AWGs), polarization insensitive ring resonators, and polarization splitters and filters are demonstrated using these design principles.

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Yokoi, Nobuhiro, Takeshi Fujisawa, Kunimasa Saitoh, and Masanori Koshiba. "Apodized photonic crystal waveguide gratings." Optics Express 14, no. 10 (2006): 4459. http://dx.doi.org/10.1364/oe.14.004459.

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Chen, Chao, Xuechun Li, Kun Xu, Jian Wu, and Jintong Lin. "Photonic crystal waveguide sampled gratings." Optics Communications 276, no. 2 (August 2007): 237–41. http://dx.doi.org/10.1016/j.optcom.2007.04.043.

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Kakoolaki, Nazanin, and Abdollah Hassanzadeh. "Waveguide gratings with metamaterial films." Journal of the Optical Society of America B 37, no. 8 (July 15, 2020): 2353. http://dx.doi.org/10.1364/josab.386117.

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Kumar, Mahesh, Jani Tervo, Tommi Kaplas, and Yuri Svirko. "Graphene-enhanced waveguide-resonance gratings." Journal of Nanophotonics 10, no. 1 (December 10, 2015): 012518. http://dx.doi.org/10.1117/1.jnp.10.012518.

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38

Tsoi, H. C., W. H. Wong, and E. Y. B. Pun. "Polymeric long-period waveguide gratings." IEEE Photonics Technology Letters 15, no. 5 (May 2003): 721–23. http://dx.doi.org/10.1109/lpt.2003.810257.

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Zhao, C. Y., P. Y. Chen, and C. M. Zhang. "Numerical analysis of Bragg grating-based slot-micro-ring coupling resonator system for electromagnetically-induced transparency-like effect." Modern Physics Letters B 34, no. 28 (June 15, 2020): 2050307. http://dx.doi.org/10.1142/s0217984920503078.

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We propose a novel bio-sensor structure composed of double sided-wall Bragg gratings and dual-slot-micro-ring waveguides. The slot waveguide is a better choice to interact the bio-material under investigation with the propagating light with in the slot region. The incident light field propagates clockwise through the slot micro-ring resonator, the reflection light field propagates counterclockwise in the slot Bragg grating. By optimizing the geometric parameters of the device, the spectral response is tailored to obtain a sharp resonant peak simulated by the finite- difference time-domain (FDTD) method. The spectrum can be tuned not only by geometrically changing the couple distance in slot Bragg grating resonator, but also by dynamically altering the depth and number of the Bragg grating. Furthermore, the device is easy to yield an extinction ratio of 11 dB, a FWHM of 1.1 nm and a quality factor of [Formula: see text]. The device with a small footprint can enable integration with some photonic devices on a chip and have great promising for applications including tunable sensors, slow-light devices and optical communication.

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40

Liu, Wei-Nan, Rui Chen, Wei-Yi Shi, Ke-Bo Zeng, Fu-Li Zhao, and Jian-Wen Dong. "Narrow-frequency sharp-angular filters using all-dielectric cascaded meta-gratings." Nanophotonics 9, no. 10 (June 17, 2020): 3443–50. http://dx.doi.org/10.1515/nanoph-2020-0141.

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AbstractSelective transmission or filtering always responds to either frequency or incident angle, so as hardly to maximize signal-to-noise ratio in communication, detection and sensing. Here, we propose compact meta-filters of narrow-frequency sharp-angular transmission peak along with broad omnidirectional reflection sidebands, in all-dielectric cascaded subwavelength meta-gratings. The inherent collective resonance of waveguide-array modes and thin film approximation of meta-grating are employed as the design strategy. A unity transmission peak, locating at the incident angle of 44.4° and the center wavelength of 1550 nm, is demonstrated in a silicon meta-filter consisting of two-layer silicon rectangular meta-grating. These findings provide possibilities in cascaded meta-gratings spectroscopic design and alternative utilities for high signal-to-noise ratio applications in focus-free spatial filtering and anti-noise systems in telecommunications.

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Meyer, Jan, Antonio Nedjalkov, Christian Kelb, Gion Joel Strobel, Leonhard Ganzer, and Wolfgang Schade. "Manufacturing and Characterization of Femtosecond Laser-Inscribed Bragg Grating in Polymer Waveguide Operation in an IR-A Wavelength Range." Sensors 20, no. 1 (January 1, 2020): 249. http://dx.doi.org/10.3390/s20010249.

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Optical sensors, such as fiber Bragg gratings, offer advantages compared to other sensors in many technological fields due to their outstanding characteristics. This sensor technology is currently transferred to polymer waveguides that provide the potential for cost-effective, easy, and flexible manufacturing of planar structures. While sensor production itself, in the majority of cases, is performed by means of phase mask technique, which is limited in terms of its degrees of freedom, other inscription techniques enable the manufacture of more adaptable sensor elements for a wider range of applications. In this article, we demonstrate the point-by-point femtosecond laser direct inscription method for the processing of polymer Bragg gratings into waveguides of the epoxy-based negative photoresist material EpoCore for a wavelength range around 850 nm. By characterizing the obtained grating back-reflection of the produced sensing element, we determined the sensitivity for the state variables temperature, humidity, and strain to be 45 pm/K, 19 pm/%, and 0.26 pm/µε, respectively. Individual and more complex grating structures can be developed from this information, thus opening new fields of utilization.

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Wang, Jian Gang, Zhan Jun Yan, and Wen Qiang Li. "Optical Design of Waveguide Holographic Binocular Display for Machine Vision." Applied Mechanics and Materials 427-429 (September 2013): 763–69. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.763.

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A binocular display can satisfy competition mechanism of biological vision system and improve display precision. A binocular optical system is designed with waveguide holography (WGH) for small size and light weight. A superimposed holographic volume grating can split the image bearing lights into two equal intensity light beams. The out-coupling waveguide holographic gratings for the left and right eyes can implement image extension and imaging display. The simulation and experimental results reveal that excellent optical performances can be achieved for little distortion of less than 0.05%(nearly zero), light weight of about only 32g, and compact size. The display information can also be overlaid the outside scenes in eyeglass augmented reality and Machine Vision Display applications.

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Tripathi, U. S., and Vipul Rastogi. "Temperature insensitive long period waveguide gratings in rib waveguide." Optik 186 (June 2019): 15–21. http://dx.doi.org/10.1016/j.ijleo.2019.04.071.

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Puumala, Lauren S., Samantha M. Grist, Kithmin Wickremasinghe, Mohammed A. Al-Qadasi, Sheri Jahan Chowdhury, Yifei Liu, Matthew Mitchell, Lukas Chrostowski, Sudip Shekhar, and Karen C. Cheung. "An Optimization Framework for Silicon Photonic Evanescent-Field Biosensors Using Sub-Wavelength Gratings." Biosensors 12, no. 10 (October 8, 2022): 840. http://dx.doi.org/10.3390/bios12100840.

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Silicon photonic (SiP) evanescent-field biosensors aim to combine the information-rich readouts offered by lab-scale diagnostics, at a significantly lower cost, and with the portability and rapid time to result offered by paper-based assays. While SiP biosensors fabricated with conventional strip waveguides can offer good sensitivity for label-free detection in some applications, there is still opportunity for improvement. Efforts have been made to design higher-sensitivity SiP sensors with alternative waveguide geometries, including sub-wavelength gratings (SWGs). However, SWG-based devices are fragile and prone to damage, limiting their suitability for scalable and portable sensing. Here, we investigate SiP microring resonator sensors designed with SWG waveguides that contain a “fishbone” and highlight the improved robustness offered by this design. We present a framework for optimizing fishbone-style SWG waveguide geometries based on numerical simulations, then experimentally measure the performance of ring resonator sensors fabricated with the optimized waveguides, targeting operation in the O-band and C-band. For the O-band and C-band devices, we report bulk sensitivities up to 349 nm/RIU and 438 nm/RIU, respectively, and intrinsic limits of detection as low as 5.1 × 10−4 RIU and 7.1 × 10−4 RIU, respectively. This performance is comparable to the state of the art in SWG-based sensors, positioning fishbone SWG resonators as an attractive, more robust, alternative to conventional SWG designs.

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Passoni, Marco, Dario Gerace, Liam O’Faolain, and Lucio Claudio Andreani. "Slow light with interleaved p-n junction to enhance performance of integrated Mach-Zehnder silicon modulators." Nanophotonics 8, no. 9 (May 30, 2019): 1485–94. http://dx.doi.org/10.1515/nanoph-2019-0045.

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AbstractSlow light is a very important concept in nanophotonics, especially in the context of photonic crystals. In this work, we apply our previous design of band-edge slow light in silicon waveguide gratings [M. Passoni et al, Opt. Express 26, 8470 (2018)] to Mach-Zehnder modulators based on the plasma dispersion effect. The key idea is to employ an interleaved p-n junction with the same periodicity as the grating, in order to achieve optimal matching between the electromagnetic field profile and the depletion regions of the p-n junction. The resulting modulation efficiency is strongly improved as compared to common modulators based on normal rib waveguides, even in a bandwidth of 20–30 nm near the band edge, while the total insertion loss due to free carriers is not increased. The present concept is promising in view of realizing slow-light modulators for silicon photonics with reduced energy dissipation.

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Meng You, Meng You, Zhanhua Huang Zhanhua Huang, and Huaiyu Cai and Huaiyu Cai. "Design of Waveguide Head-Up Display with Embedded Gratings." Chinese Journal of Lasers 39, no. 9 (2012): 0916001. http://dx.doi.org/10.3788/cjl201239.0916001.

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Malayappan, Balasubramanian, Narayan Krishnaswamy, and Prasant Kumar Pattnaik. "Novel High-Resolution Lateral Dual-Axis Quad-Beam Optical MEMS Accelerometer Using Waveguide Bragg Gratings." Photonics 7, no. 3 (July 18, 2020): 49. http://dx.doi.org/10.3390/photonics7030049.

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A novel lateral dual-axis a-Si/SiO2 waveguide Bragg grating based quad-beam accelerometer with high-resolution and large linear range has been presented in this paper. The sensor consists of silicon bulk micromachined proof mass suspended by silica beams. Three ridge gratings are positioned on the suspending beam and proof mass to maximize sensitivity and reduce noise. Impact of external acceleration in the sensing direction on the Bragg wavelength of gratings and MEMS structure has been modelled including the effects of strain, stress and temperature variation. Acceleration induces stress in the beam thus modifying the grating period and introducing chirp. The differential wavelength shift with respect to reference grating on the proof mass is the measure of acceleration. To compensate for the effect of the weight of the proof mass and increase the sensitivity of the sensor, electrostatic force of repulsion is applied to the proof mass. For the chosen parameters, the designed sensor has a linear response over a large range and a sensitivity of 30 pm/g. The temperature of surroundings, which acts as noise in sensor performance is compensated by taking differential wavelength shift with respect to reference grating. By design and choice of material, low cross-axis sensitivity is achieved. The proposed design enables a high-resolution well below 1 μ g/ Hz and is suitable for inertial navigation and seismometry applications.

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Kopenkin S. S., Kesaev V. V., and Putilin A. N. "Method for measuring periods of waveguide diffractive optical elements." Technical Physics Letters 48, no. 15 (2022): 34. http://dx.doi.org/10.21883/tpl.2022.15.53818.18953.

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An original method of the periods of waveguide diffractive optical elements (DOEs) measuring is proposed. In contrast to standard techniques, the proposed method provides measurements of waveguide gratings periods while the diffracted light is propagating in the substrate material. The method is simple and has a small error Keywords: waveguide holograms, diffractive optical elements.

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Guo, Jin Song, Zhao Xia Wang, Hai Dong Wu, and Yun Wen Wu. "Investigation of Broadband Wavelength Conversion Based on Cascaded Second-Harmonic Generation and Difference Frequency Generation." Applied Mechanics and Materials 738-739 (March 2015): 759–62. http://dx.doi.org/10.4028/www.scientific.net/amm.738-739.759.

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Step-chirped gratings is utilized to broaden the bandwidth of wavelength conversion based on single-pass/ double-pass cascaded second harmonic generation and difference frequency generation. By adding the step-chirped gratings number and optimizing the poling period, broad conversion bandwidth and flat response can be obtained simultaneously. The bandwidth of 4-cm-long waveguide with 6-section chirped gratings are 169 nm for single-pass scheme and 164 nm for the double-pass one, which are 98 nm and 101 nm larger than those of uniform gratings, respectively. Furthermore, comparison between step-chirped gratings and equal-segmented gratings is carried out.

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Zhizhchenko, Alexey Yu, Yuri N. Kulchin, Oleg B. Vitrik, Anatoly G. Mirochnik, and Elena V. Fedorenko. "Photorecording Polymeric Waveguide Film Based on 2,2-difluoro-4-(9-anthracyl)-6-methyl-1,3,2-dioksaborine for Photonics." Solid State Phenomena 213 (March 2014): 170–75. http://dx.doi.org/10.4028/www.scientific.net/ssp.213.170.

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In this paper the possibility of using the novel polymeric photosensitive medium for the fabrication of integrated optics elements was demonstrated. The medium is based on PMMA doped by beta-diketonatoboron difluorides. Planar and strip waveguides with the attenuation losses less than 1.8 dB/cm were fabricated in the layer of the medium. The photoinduced recording of the diffraction grating with the spatial frequency up to 3000 mm-1and diffraction efficiency ~5% in such waveguides was demonstrated. The possibility to improve the diffraction efficiency of recorded gratings up to 51% by chemical treatment was demonstrated.

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Journal articles on the topic 'Waveguide gratings'

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