- 标题
- 摘要
- 关键词
- 实验方案
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Modal characteristics of refractive index engineered hybrid plasmonic waveguide
摘要： In this work, we proposed a novel design of a refractive index engineered subwavelength grating silicon-based hybrid plasmonic waveguide via the finite element method. The intensity integral (Γ) in the upper cladding can be controlled by varying the thickness (HSi) of the top silicon layer. The highest evanescent field ratio of 0.85 is obtained at HSi=200 nm which allows the hybrid mode to confine in the low index medium and a large evanescent field resides in the upper cladding. The sensitivity of the waveguide is calculated by monitoring the change in the effective refractive index to the ambient refractive index. The maximum mode sensitivity of 0.7 is obtained. The spectral performance of the subwavelength grating (SWG) hybrid plasmonic waveguide (HPWG) based ring resonator design is studied which exhibits a sensitivity as high as 1000 nm/RIU which is higher than the previously reported values. We believe that the proposed waveguide scheme is an ideal candidate to produce highly sensitive lab-on-chip sensors.
关键词： microring resonator,refractive index sensor,Subwavelength grating hybrid plasmonic waveguide,Evanescent field ratio
更新于2025-09-23 15:21:01
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Silicon High-order Mode (De)Multiplexer on Single Polarization
摘要： Mode-division multiplexing on an integrated photonic chip is critical for future optical networks. High-order mode multiplexing is desired to increase the transmission capacity. Here we propose and experimentally demonstrate a silicon on-chip high-order mode (de)multiplexer using subwavelength grating (SWG) structure, which supports 11-mode (de)multiplexing on a TE-polarized light (TE0 ~ TE10). The proposed mode (de)multiplexer comprises three directional couplers and seven SWG-based directional couplers. Measurement results show that all the 11 channels have low crosstalk values (?15.4 dB ~ ?26.4 dB) and low insertion losses (0.1 dB ~ 2.6 dB) at 1545 nm. To the best of our knowledge, our device achieves the highest-order-mode (de)multiplexing on a silicon photonic chip.
关键词： photonic integrated circuits,silicon photonics,multiplexing,Subwavelength grating,mode
更新于2025-09-23 15:21:01
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Dual-wavelengths filter operating at visible wavelength region using subwavelength grating on waveguide structure
摘要： A dual-wavelength filter was experimentally demonstrated using subwavelength grating (SWG)/waveguide structure. We designed the structural parameters of the SWG and the waveguide to find the reflection peaks in the visible wavelength region. To investigate the optical response of the designed SWG/waveguide structure, finite-difference time-domain (FDTD) numerical calculations were performed for electromagnetic field distribution. The dual reflection peaks from our proposed structure were predicted in visible wavelength regions by the FDTD calculation. The calculated electromagnetic field distribution also revealed that the reflection peaks were associated with resonances in the SWG and waveguides. We fabricated the SWG/waveguide with typical electron-beam lithography techniques, and two reflection peaks were observed at wavelengths of 486 nm and 590 nm with bandwidths of 45 nm and 58 nm, respectively. These experimental results indicate that dual-wavelength filters can be successfully realized without complex fabrication processes.
关键词： Dual-wavelength filter,Waveguide,Guided mode,Subwavelength grating
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Polarization-insensitive Waveguide Crossings Based on SWGs-assisted MMI
摘要： A polarization-insensitive waveguide crossing based on sub-wavelength gratings (SWGs) assisted multimode interference (MMI) is proposed and demonstrated on silicon-on-insulator (SOI) platform. The proposed device is characterized with low insertion loss and low crosstalk for both TE and TM polarizations from 1500 nm to 1600 nm, 0.69 dB (0.61 dB) for TE (TM) at 1550 nm. The device can be fabricated with single etch process to achieve a footprint of 12.5×12.5 μm2. Further analysis shows that the device has a fabrication tolerance of ±30 nm for the MMI structure. The proposed device can be employed in photonic integrated circuits with polarization-division-(de)multiplexing functionality.
关键词： Waveguide crossing,Polarization-insensitive,Subwavelength grating,MMI
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Liquid Crystal Tunable Narrow Linewidth Filter Based On Subwavelength Gratings Reflector
摘要： We present a electro-tunable liquid crystal (LC) filter consisting of a DBRs and SWGs reflectors which enables uniform alignment of LC. The filter achieve a wide-continuous tuning range of 60 nm and a linewidth of less than 1 nm.
关键词： optical microcavity,subwavelength grating,liquid crystal,tunable
更新于2025-09-16 10:30:52
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Integrated color photodetectors in 40 nm standard CMOS technology
摘要： For the further integration of receivers in multi-color visible light communication systems, a novel color photodetector (PD) was designed and fabricated by using a 40 nm standard complementary metal oxide semiconductor (CMOS) process without any process modifications. The PD consists of CMOS photodiode and two-dimensional (2D) polysilicon subwavelength grating above the photodiode. The 2D polysilicon grating is controlled in structural parameters to realize color filtering, based on guided-mode resonance, for the first time in a standard CMOS process. Here three kinds of color PDs were designed to respond to the three primary colors. The measured results demonstrate that the color PDs exhibit wavelength selectivity in the visible range (400-700 nm) and the maximum peaks in the spectral response curves of them are at 660 nm (red), 585 nm (green) and 465 nm (blue), respectively. In addition, the added 2D polysilicon grating almost does not reduce the responsivity of the photodiodes.
关键词： two-dimensional polysilicon subwavelength grating,Color photodetector,visible light communication,complementary metal oxide semiconductor (CMOS)
更新于2025-09-12 10:27:22
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Mode Sensitivity Analysis of Subwavelength Grating Slot Waveguides
摘要： In this paper, we investigate the mode sensitivity (Smode) of subwavelength grating slot (SWGS) waveguides. Smode is an important parameter in various waveguide-based photonic circuits such as sensors, modulators, and thermally-controlled devices. It is a measure of the sensitivity of the waveguide effective index towards the refractive index perturbations in the cladding medium. The SWGS waveguide exhibits high mode sensitivity, as it combines sensitivity enhancement features of both slot and subwavelength grating waveguides. Finite-difference time-domain simulations are performed for the analysis, design, and optimization of the hybrid structure. The SWGS waveguide is incorporated into a Mach-Zehnder interferometer and fabricated on a silicon-on-insulator platform for the experimental estimation of Smode. The measured Smode value of 79% is consistent with the theoretical prediction of 83%.
关键词： Subwavelength grating,sensor,silicon-on-insulator,integrated optics,slot waveguide
更新于2025-09-11 14:15:04
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Wavelength-Flattened Directional Coupler Based Mid-Infrared Chemical Sensor Using Bragg Wavelength in Subwavelength Grating Structure
摘要： In this paper, we report a compact wavelength-flattened directional coupler (WFDC) based chemical sensor featuring an incorporated subwavelength grating (SWG) structure for the mid-infrared (MIR). By incorporating a SWG structure into directional coupler (DC), the dispersion in DC can be engineered to allow broadband operation which is advantageous to extract spectroscopic information for MIR sensing analysis. Meanwhile, the Bragg reflection introduced by the SWG structure produces a sharp trough at the Bragg wavelength. This sharp trough is sensitive to the surrounding refractive index (RI) change caused by the existence of analytes. Therefore, high sensitivity can be achieved in a small footprint. Around fivefold enhancement in the operation bandwidth compared to conventional DC is achieved for 100% coupling efficiency in a 40 μm long WFDC experimentally. Detection of dichloromethane (CH2Cl2) in ethanol (C2H5OH) is investigated in a SWG-based WFDC sensor 136.8 μm long. Sensing performance is studied by 3D finite-difference time domain (FDTD) simulation while sensitivity is derived by computation. Both RI sensing and absorption sensing are examined. RI sensing reveals a sensitivity of ?0.47% self-normalized transmitted power change per percentage of CH2Cl2 concentration while 0.12% change in the normalized total integrated output power is realized in the absorption sensing. As the first demonstration of the DC based sensor in the MIR, our device has the potential for tertiary mixture sensing by utilizing both changes in the real and imaginary part of RI. It can also be used as a broadband building block for MIR application such as spectroscopic sensing system.
关键词： subwavelength grating,waveguide coupler,nanophotonics,photonics sensors,mid-infrared
更新于2025-09-10 09:29:36