The Experts below are selected from a list of 3447 Experts worldwide ranked by ideXlab platform
Yaocheng Shi - One of the best experts on this subject based on the ideXlab platform.
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flat top cwdm de multiplexers based on contra Directional Couplers with subwavelength gratings
IEEE Photonics Technology Letters, 2019Co-Authors: Jingye Chen, Yaocheng ShiAbstract:A coarse wavelength division multiplexing (CWDM) (de)multiplexer based on the contra-Directional Couplers (contra-DCs) with subwavelength grating (SWG) waveguide is proposed and demonstrated on the silicon-on-insulator (SOI) platform. By utilizing the SWG waveguides with strong coupling strength, the coupling length can be significantly reduced and the transmission spectra are flat-top. The footprint of the demonstrated device is about $15\times 160\,\,\mu \text{m}^{2}$ . The proposed device is characterized with large bandwidth and low crosstalk at C-band.
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flat top cwdm de multiplexer based on mzi with bent Directional Couplers
IEEE Photonics Technology Letters, 2018Co-Authors: Yaocheng ShiAbstract:A low-crosstalk and flat-top 4-channel coarse wavelength-division multiplexing (de)multiplexer is proposed and demonstrated. The cascaded Mach-Zehnder interferometers are used to provide flat pass-bands. By utilizing the power splitters based on the bent Directional Couplers, the crosstalk of the Mach-Zehnder interferometers could be ultra-low for all four channels. The measurement results of the fabricated device show that the crosstalk is $\sim 300~\mu \text{m} \times 100~\mu \text{m}$ .
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ultra compact polarization independent Directional Couplers utilizing a subwavelength structure
Optics Letters, 2017Co-Authors: Yaocheng ShiAbstract:Ultra-compact polarization-independent Directional Couplers are proposed and demonstrated on the silicon-on-insulator (SOI) platform. By using the subwavelength structure in the coupling region, the coupling strength is greatly enhanced only for TE polarization, so that the coupling strength could be equivalent between TE and TM polarizations. Both complete coupling and 3 dB splitting have been demonstrated. The coupling length could be as short as ∼3.75 μm. The measured excess losses and polarization dependence losses are <∼1 and <∼0.5 dB.
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an ultracompact silicon triplexer based on cascaded bent Directional Couplers
Journal of Lightwave Technology, 2017Co-Authors: Jingye Chen, Yaocheng ShiAbstract:A novel on-chip triplexer based on bent Directional Couplers has been demonstrated to separate the 1310 nm wavelength band (∼100 nm wide bandwidth) into one port and 1490 and 1550 nm wavelength bands into the other two ports. By utilizing bent Directional Couplers, the footprint of the total device can be reduced to 19 × 31 μ m2, which is an ultracompact triplexer with high performance ever demonstrated. The simulated high-performance device, easily fabricated with only one fully etching step, is also characterized with low crosstalk (∼–15 dB) and <1 dB insertion loss.
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polarization insensitive broadband 2 2 3 db power splitter based on silicon bent Directional Couplers
Optics Letters, 2017Co-Authors: Xun Chen, Weixi Liu, Yuguang Zhang, Yaocheng ShiAbstract:We present and demonstrate a broadband and polarization-insensitive 2×2 3 dB power splitters based on silicon-bent Directional Couplers (DCs). The working bandwidth can be from 1520 to 1630 nm for both TE and TM polarizations, with an excess loss less than 1 dB. The total size for the fabricated device can be as small as 50 μm, and the measurement results show good agreement with the simulations.
Lukas Chrostowski - One of the best experts on this subject based on the ideXlab platform.
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fsr free silicon on insulator microring resonator based filter with bent contra Directional Couplers
Optics Express, 2016Co-Authors: Nourhan Eid, Lukas Chrostowski, Wei Shi, Robert Boeck, Hasitha Jayatilleka, Nicolas A. F. JaegerAbstract:High-speed optical interconnects drive the need for compact microring resonators (MRRs) with wide free spectral ranges (FSRs). A silicon-on-insulator MRR based filter with bent contra-Directional Couplers that exhibits an FSR-free response, at both the drop and through ports, while achieving a compact footprint is both theoretically and experimentally demonstrated. Also, using bent contra-Directional Couplers in the couping regions of MRRs allowed us to achieve larger side-mode suppressions than MRRs with straight CDCs. The fabricated filter has a minimum suppression ratio of more than 15 dB, a 3dB-bandwidth of ~23 GHz, an extinction ratio of ~18 dB, and a drop-port insertion loss of ~1 dB. High-speed data transmission through our filter is also demonstrated at data rates of 12.5 Gbps, 20 Gbps, and 28 Gbps.
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compact broadband Directional Couplers using subwavelength gratings
IEEE Photonics Journal, 2016Co-Authors: Yun Wang, Han Yun, Nicolas A. F. Jaeger, Fan Zhang, Lukas ChrostowskiAbstract:We experimentally demonstrate compact broadband Directional Couplers using subwavelength gratings for silicon-on-insulator wafers with silicon layers of 220 nm. The dispersion properties of the optical modes are engineered using subwavelength gratings, which allow broadband operation. Finite-difference time-domain (FDTD)-based band structure calculations, with significantly reduced simulation time, were used to analyze the design, which included both the structure and material dispersions. Compact broadband direction Couplers, with device lengths shorter than 14 $\mu\text{m}$ , which cover a bandwidth of 100 nm for power splitting ratios of 50/50, 40/60, 30/70, and 20/80, are designed and fabricated for the fundamental transverse electric mode with a central operating wavelength of 1550 nm.
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silicon cwdm demultiplexers using contra Directional Couplers
Conference on Lasers and Electro-Optics, 2013Co-Authors: Wei Shi, Charlie Lin, Han Yun, Jonas Flueckiger, Nicolas A. F. Jaeger, Yun Wang, Xu Wang, Lukas ChrostowskiAbstract:We experimentally demonstrate ultra-compact (<0.008mm2), 4-channel CWDM demultiplexers using silicon photonic contra-Directional Couplers. Flat-top passbands of 10nm, insertion loss of lower than 1dB, and crosstalk of −20dB have been obtained.
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silicon photonic grating assisted contra Directional Couplers
Optics Express, 2013Co-Authors: Wei Shi, Charlie Lin, Han Yun, Nicolas A. F. Jaeger, Xu Wang, Yang Liu, Tom Baehrjones, Michael Hochberg, Lukas ChrostowskiAbstract:We demonstrate, in both theory and experiment, 4-port, electrically tunable photonic filters using silicon contra-Directional Couplers (contra-DCs) with uniform and phase-shifted waveguide Bragg gratings. Numerical analysis, including both intra- and inter-waveguide couplings, is performed using coupled-mode theory and the transfer-matrix method. The contra-DC devices were fabricated by a CMOS-photonics manufacturing foundry and are electrically tunable using free-carrier injection. A 4-port, grating-based photonic resonator has been obtained using the phase-shifted contra-DC, showing a resonant peak with a 3-dB bandwidth of 0.2 nm and an extinction ratio of 24 dB. These contra-DC devices enable on-chip integration of Bragg-grating-defined functions without using circulators and have great potential for applications such as wavelength-division multiplexing networks and optical signal processing.
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Ultra-compact, flat-top demultiplexer using anti-reflection contra-Directional Couplers for CWDM networks on silicon
Optics Express, 2013Co-Authors: Wei Shi, Sahba Talebi Fard, Charlie Lin, Han Yun, Mark Greenberg, Jonas Flueckiger, Nicolas A. F. Jaeger, Yun Wang, Xu Wang, Lukas ChrostowskiAbstract:Wavelength-division-multiplexing (WDM) networks with wide channel grids and bandwidths are promising for low-cost, low-power optical interconnects. Wide-bandwidth, single-band (i.e., no free-spectral range) add-drop filters have been developed on silicon using anti-reflection contra-Directional Couplers with out-of-phase Bragg gratings. Using such filter components, we demonstrate a 4-channel, coarse-WDM demultiplexer with flat passbands of up to 13 nm and an ultra-compact size of 1.2 × 10(-3) mm(2).
Slawomir Gruszczynski - One of the best experts on this subject based on the ideXlab platform.
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Differentially Fed Directional Couplers With Coupled-Conductors of Unequal Widths
IEEE Microwave and Wireless Components Letters, 2018Co-Authors: Konrad Janisz, Krzysztof Wincza, Ilona Piekarz, Kamil Staszek, Slawomir GruszczynskiAbstract:In this letter, coupled-line Directional Couplers with differentially excited balanced coupled lines are considered in which balanced lines having different widths are proposed. Different conductor widths allow for coupling control within a chosen dielectric stack-up and give design freedom in terms of coupling adjustment. The theoretical analysis is confirmed by experimental verification, in which a broadband asymmetrical 3-dB two-section Directional coupler has been designed and measured.
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Rigorous Approach for Design of Differential Coupled-Line Directional Couplers Applicable in Integrated Circuits and Substrate-Embedded Networks
Scientific Reports, 2016Co-Authors: Kamil Staszek, Krzysztof Wincza, Slawomir GruszczynskiAbstract:We report rigorous approach for the design of differential coupled-line Directional Couplers in multilayer dielectric structures. In the proposed procedure numerically calculated per-unit-length parameters of coupled transmission lines are utilized for derivation of differential Couplers’ properties. The known description technique with multimode scattering parameters has been extended to the eight-ports considered in the paper and the properties resulting from symmetry of the considered networks have been shown. Exemplary 3-dB and 8-dB coupled-line Directional Couplers have been designed and experimentally evaluated. Nodal to mixed-mode conversion of scattering parameters has been applied to allow for measurements of the physically realized models. Results of measurements are shown to confirm the presented theoretical considerations.
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broadband planar fully integrated 8 times 8 butler matrix using coupled line Directional Couplers
IEEE Transactions on Microwave Theory and Techniques, 2011Co-Authors: Krzysztof Wincza, Slawomir Gruszczynski, K SachseAbstract:An innovative approach that allows for realization of broadband planar fully integrated 8 × 8 Butler matrices is presented. Coupled-line Directional Couplers have been utilized, which enable broad operational band. A novel arrangement of the network has been proposed that allows the creation of an entirely planar design having two metallization layers and no interconnections between these layers. Four selected crossovers have been realized as a tandem connection of two 3-dB/90° coupled-line Directional Couplers, which, together with reference lines having appropriate electrical lengths, perform simultaneously crossovers of signal lines, and all needed broadband constant value phase shifters. Moreover, two of the needed 3-dB/90° Directional Couplers have been designed as tandem connections of two 8.34-dB Directional Couplers, acting as 3-dB/90° Directional Couplers having crossed outputs. With such a modification, a fully planar design with no inter-layer connections is possible. The proposed network arrangement has been experimentally tested with the design of an 8 × 8 Butler matrix operating at the center frequency of 3 GHz. The obtained measurement results fully confirm the validity of the proposed approach.
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asymmetric coupled line Directional Couplers as impedance transformers in balanced and n way power amplifiers
IEEE Transactions on Microwave Theory and Techniques, 2011Co-Authors: Krzysztof Wincza, Slawomir GruszczynskiAbstract:Asymmetric 3-dB coupled-line Directional Couplers for application in balanced circuits have been considered, and it has been theoretically shown that such Couplers allow for simultaneous (equal) power division and impedance transformation. A limitation on achievable impedance ratio has been derived. The theoretical analysis has been experimentally verified by the measurements of a number of passive circuits and an exemplary application of the proposed circuits in a four-way power amplifier has been shown.
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miniaturized quasi lumped coupled line single section and multisection Directional Couplers
IEEE Transactions on Microwave Theory and Techniques, 2010Co-Authors: Krzysztof Wincza, Slawomir GruszczynskiAbstract:A class of lumped-element coupled-line Directional Couplers has been investigated. The paper discusses the influence of the number of coupler's subsections on the overall Couplers' performance. The design procedure for calculating elements of the coupler for the chosen coupling C and the number of coupler's subsections has been proposed. The design procedure has been experimentally verified by the measurements of a single-section Directional coupler. Also, an asymmetric two-section coupler not reported in the literature has been designed using a lumped-element technique, and the experimental results are shown.
Krzysztof Wincza - One of the best experts on this subject based on the ideXlab platform.
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Differentially Fed Directional Couplers With Coupled-Conductors of Unequal Widths
IEEE Microwave and Wireless Components Letters, 2018Co-Authors: Konrad Janisz, Krzysztof Wincza, Ilona Piekarz, Kamil Staszek, Slawomir GruszczynskiAbstract:In this letter, coupled-line Directional Couplers with differentially excited balanced coupled lines are considered in which balanced lines having different widths are proposed. Different conductor widths allow for coupling control within a chosen dielectric stack-up and give design freedom in terms of coupling adjustment. The theoretical analysis is confirmed by experimental verification, in which a broadband asymmetrical 3-dB two-section Directional coupler has been designed and measured.
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Rigorous Approach for Design of Differential Coupled-Line Directional Couplers Applicable in Integrated Circuits and Substrate-Embedded Networks
Scientific Reports, 2016Co-Authors: Kamil Staszek, Krzysztof Wincza, Slawomir GruszczynskiAbstract:We report rigorous approach for the design of differential coupled-line Directional Couplers in multilayer dielectric structures. In the proposed procedure numerically calculated per-unit-length parameters of coupled transmission lines are utilized for derivation of differential Couplers’ properties. The known description technique with multimode scattering parameters has been extended to the eight-ports considered in the paper and the properties resulting from symmetry of the considered networks have been shown. Exemplary 3-dB and 8-dB coupled-line Directional Couplers have been designed and experimentally evaluated. Nodal to mixed-mode conversion of scattering parameters has been applied to allow for measurements of the physically realized models. Results of measurements are shown to confirm the presented theoretical considerations.
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broadband planar fully integrated 8 times 8 butler matrix using coupled line Directional Couplers
IEEE Transactions on Microwave Theory and Techniques, 2011Co-Authors: Krzysztof Wincza, Slawomir Gruszczynski, K SachseAbstract:An innovative approach that allows for realization of broadband planar fully integrated 8 × 8 Butler matrices is presented. Coupled-line Directional Couplers have been utilized, which enable broad operational band. A novel arrangement of the network has been proposed that allows the creation of an entirely planar design having two metallization layers and no interconnections between these layers. Four selected crossovers have been realized as a tandem connection of two 3-dB/90° coupled-line Directional Couplers, which, together with reference lines having appropriate electrical lengths, perform simultaneously crossovers of signal lines, and all needed broadband constant value phase shifters. Moreover, two of the needed 3-dB/90° Directional Couplers have been designed as tandem connections of two 8.34-dB Directional Couplers, acting as 3-dB/90° Directional Couplers having crossed outputs. With such a modification, a fully planar design with no inter-layer connections is possible. The proposed network arrangement has been experimentally tested with the design of an 8 × 8 Butler matrix operating at the center frequency of 3 GHz. The obtained measurement results fully confirm the validity of the proposed approach.
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asymmetric coupled line Directional Couplers as impedance transformers in balanced and n way power amplifiers
IEEE Transactions on Microwave Theory and Techniques, 2011Co-Authors: Krzysztof Wincza, Slawomir GruszczynskiAbstract:Asymmetric 3-dB coupled-line Directional Couplers for application in balanced circuits have been considered, and it has been theoretically shown that such Couplers allow for simultaneous (equal) power division and impedance transformation. A limitation on achievable impedance ratio has been derived. The theoretical analysis has been experimentally verified by the measurements of a number of passive circuits and an exemplary application of the proposed circuits in a four-way power amplifier has been shown.
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miniaturized quasi lumped coupled line single section and multisection Directional Couplers
IEEE Transactions on Microwave Theory and Techniques, 2010Co-Authors: Krzysztof Wincza, Slawomir GruszczynskiAbstract:A class of lumped-element coupled-line Directional Couplers has been investigated. The paper discusses the influence of the number of coupler's subsections on the overall Couplers' performance. The design procedure for calculating elements of the coupler for the chosen coupling C and the number of coupler's subsections has been proposed. The design procedure has been experimentally verified by the measurements of a single-section Directional coupler. Also, an asymmetric two-section coupler not reported in the literature has been designed using a lumped-element technique, and the experimental results are shown.
Nicolas A. F. Jaeger - One of the best experts on this subject based on the ideXlab platform.
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fsr free silicon on insulator microring resonator based filter with bent contra Directional Couplers
Optics Express, 2016Co-Authors: Nourhan Eid, Lukas Chrostowski, Wei Shi, Robert Boeck, Hasitha Jayatilleka, Nicolas A. F. JaegerAbstract:High-speed optical interconnects drive the need for compact microring resonators (MRRs) with wide free spectral ranges (FSRs). A silicon-on-insulator MRR based filter with bent contra-Directional Couplers that exhibits an FSR-free response, at both the drop and through ports, while achieving a compact footprint is both theoretically and experimentally demonstrated. Also, using bent contra-Directional Couplers in the couping regions of MRRs allowed us to achieve larger side-mode suppressions than MRRs with straight CDCs. The fabricated filter has a minimum suppression ratio of more than 15 dB, a 3dB-bandwidth of ~23 GHz, an extinction ratio of ~18 dB, and a drop-port insertion loss of ~1 dB. High-speed data transmission through our filter is also demonstrated at data rates of 12.5 Gbps, 20 Gbps, and 28 Gbps.
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compact broadband Directional Couplers using subwavelength gratings
IEEE Photonics Journal, 2016Co-Authors: Yun Wang, Han Yun, Nicolas A. F. Jaeger, Fan Zhang, Lukas ChrostowskiAbstract:We experimentally demonstrate compact broadband Directional Couplers using subwavelength gratings for silicon-on-insulator wafers with silicon layers of 220 nm. The dispersion properties of the optical modes are engineered using subwavelength gratings, which allow broadband operation. Finite-difference time-domain (FDTD)-based band structure calculations, with significantly reduced simulation time, were used to analyze the design, which included both the structure and material dispersions. Compact broadband direction Couplers, with device lengths shorter than 14 $\mu\text{m}$ , which cover a bandwidth of 100 nm for power splitting ratios of 50/50, 40/60, 30/70, and 20/80, are designed and fabricated for the fundamental transverse electric mode with a central operating wavelength of 1550 nm.
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silicon cwdm demultiplexers using contra Directional Couplers
Conference on Lasers and Electro-Optics, 2013Co-Authors: Wei Shi, Charlie Lin, Han Yun, Jonas Flueckiger, Nicolas A. F. Jaeger, Yun Wang, Xu Wang, Lukas ChrostowskiAbstract:We experimentally demonstrate ultra-compact (<0.008mm2), 4-channel CWDM demultiplexers using silicon photonic contra-Directional Couplers. Flat-top passbands of 10nm, insertion loss of lower than 1dB, and crosstalk of −20dB have been obtained.
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silicon photonic grating assisted contra Directional Couplers
Optics Express, 2013Co-Authors: Wei Shi, Charlie Lin, Han Yun, Nicolas A. F. Jaeger, Xu Wang, Yang Liu, Tom Baehrjones, Michael Hochberg, Lukas ChrostowskiAbstract:We demonstrate, in both theory and experiment, 4-port, electrically tunable photonic filters using silicon contra-Directional Couplers (contra-DCs) with uniform and phase-shifted waveguide Bragg gratings. Numerical analysis, including both intra- and inter-waveguide couplings, is performed using coupled-mode theory and the transfer-matrix method. The contra-DC devices were fabricated by a CMOS-photonics manufacturing foundry and are electrically tunable using free-carrier injection. A 4-port, grating-based photonic resonator has been obtained using the phase-shifted contra-DC, showing a resonant peak with a 3-dB bandwidth of 0.2 nm and an extinction ratio of 24 dB. These contra-DC devices enable on-chip integration of Bragg-grating-defined functions without using circulators and have great potential for applications such as wavelength-division multiplexing networks and optical signal processing.
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Ultra-compact, flat-top demultiplexer using anti-reflection contra-Directional Couplers for CWDM networks on silicon
Optics Express, 2013Co-Authors: Wei Shi, Sahba Talebi Fard, Charlie Lin, Han Yun, Mark Greenberg, Jonas Flueckiger, Nicolas A. F. Jaeger, Yun Wang, Xu Wang, Lukas ChrostowskiAbstract:Wavelength-division-multiplexing (WDM) networks with wide channel grids and bandwidths are promising for low-cost, low-power optical interconnects. Wide-bandwidth, single-band (i.e., no free-spectral range) add-drop filters have been developed on silicon using anti-reflection contra-Directional Couplers with out-of-phase Bragg gratings. Using such filter components, we demonstrate a 4-channel, coarse-WDM demultiplexer with flat passbands of up to 13 nm and an ultra-compact size of 1.2 × 10(-3) mm(2).