Flat-Top, Sharp-Edge Add-Drop Filters Using Complementary-Misalignment-Modulated Grating-Assisted Contradirectional Couplers

Qiu, Huiye; Niu, Jinchun; Liang, Xiong; Shen, Xiuqiu; Dai, Tingge; Yu, Ping; Cheng, Rui

doi:10.1109/jlt.2021.3092045

Cited by 8 publications

(3 citation statements)

References 20 publications

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“…Note that the apodization is applied in a complementary manner to avoid phase errors for a rapid roll-off factor in the response spectrum. [28] We now scale the concept to multiple mode reflections for multiple WDM channels. Here the multiple coupling coefficients are manipulated to be several periodic curves by the dielectric hole arrays, which can provide phase-matching conditions for multiple modes simultaneously.…”

Section: Design and Analysismentioning

confidence: 99%

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On‐Chip Metamaterial Enabled Wavelength (De)Multiplexer

Zhao

Xiang

et al. 2022

Laser & Photonics Reviews

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Wavelength‐division multiplexing (WDM) technology can offer considerable parallelism for large‐capacity data communications. While several configurations have been demonstrated to realize on‐chip WDM systems, their practical applications might be hindered by large footprints or compromised performances. Recently, metamaterial‐assisted silicon photonics is emerging for on‐chip light manipulation by subwavelength‐scale control of optical wavefronts. They can reach more compact footprints and broadband functionalities beyond the classical waveguide‐based architectures. Herein, wavelength (de)multiplexers are experimentally demonstrated in the subwavelength‐structured metamaterials regime with highly compact footprints. Two‐dimensional metamaterials composed of quasi‐periodic dielectric perturbation arrays patterned on a multimode waveguide are proposed to stimulate multiple high‐order waveguide modes at different wavelengths, which are then coupled to different WDM channels by cascading mode (de)multiplexers. The four‐channel wavelength (de)multiplexer is demonstrated in a box‐like spectrum with a compact footprint of 2.5 × 250 µm2, with the measured losses less than 2 dB and channel crosstalk less than –14.3 dB. By varying the patterned metamaterial structures, the proposed devices also have the merits of flexible operating wavelengths and bandwidths. The concept features large scalability, compactness, and competitive performance, which can offer versatile on‐chip light manipulation and significantly improve the integration density for various on‐chip WDM optical systems.

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Section: Design and Analysismentioning

confidence: 99%

“…Note that the apodization is applied in a complementary manner to avoid phase errors for a rapid roll‐off factor in the response spectrum. [ 28 ]…”

Section: Design and Analysismentioning

confidence: 99%

On‐Chip Metamaterial Enabled Wavelength (De)Multiplexer

Zhao

Xiang

et al. 2022

Laser & Photonics Reviews

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“…Grating‐assisted contra‐directional coupler (GACDC) is an important optical component, which has widely been investigated in other PIC platforms, since GACDC structures can be used as fundamental building blocks that enable a range of passive devices including optical (de)multiplexer, [ 18 ] filter, [ 19–21 ] and splitter. [ 22 ] Furthermore, the GACDC‐based devices usually exhibit advantages such as a flat‐top spectral response, high design flexibility and scalability, and free spectrum range (FSR)‐free operation.…”

Section: Introductionmentioning

confidence: 99%

Subwavelength Grating‐Assisted Contra‐Directional Couplers in Lithium Niobate on Insulator

Han

Jiang

Xiao

et al. 2023

Laser & Photonics Reviews

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Grating‐assisted contra‐directional couplers are important optical components in photonic integrated circuits (PICs), which can serve as fundamental building blocks for optical (de)multiplexers, switches, filters, and splitters, among others. Recently, lithium niobate on insulator (LNOI) has emerged as an attractive PIC platform with many important active photonic circuit components demonstrated, including electro‐optic modulators and second‐harmonic wavelength converters. Nevertheless, the LNOI component toolbox still lacks some passive photonic circuit components to fulfill the requirements of future high‐performance PICs. In this contribution, a subwavelength grating‐assisted contra‐directional coupler (GACDC) is proposed, designed, and experimentally demonstrated in a silicon nitride‐loaded LNOI waveguide platform. As an example of its applications, a three‐channel wavelength‐division (de)multiplexer is fabricated and experimentally demonstrated by cascading several GACDCs, with a narrow wavelength spacing of 3.2 nm (400 GHz). The measured device insertion loss of each channel is about 2.5 dB with low interchannel crosstalk below −20 dB. A fabrication tolerance analysis is also carried out, indicating that the proposed GACDCs are tolerant to waveguide width variations.

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Electro-optic tunable grating-assisted optical waveguide directional coupler in lithium niobate

Chen²

2023

Appl. Phys. B

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In this paper, a high-performance electro-optical tunable grating-assisted directional coupler (GADC) is proposed and demonstrated experimentally. Our proposed GADC consists of a two-mode waveguide (TMW) and a single-mode waveguide (SMW) formed with lithium niobite (LN). By introducing a longperiod waveguide grating into the side-wall of the TMW to compensate for the phase mismatch of the fundamental modes of the SMW and TMW, the fundamental modes of the two waveguides can be coupled e ciently each other at a speci c wavelength. Furthermore, push-pull electrode structure is introduced to achieve the electro-optic (EO) tuning function featuring high speed, low driving voltage, and large tuning range. The best LN GADC we fabricated on x-cut LN substrate using annealing proton exchange process shows a high isolation of ~ 34 dB at 1532.9 nm wavelength, quite large EO tuning e ciency of 1.195 nm/V (1526.4-1549.1 nm) or 1.736 nm/V (1576.1-1602.2 nm), and a thermo-optic tuning e ciency of 0.128 nm/°C (22 °C-60 °C). Our proposed LN GADC can nd applications in the elds of high-speed tunable wavelength ltering, mode ltering, and EO modulation.

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Flat-Top, Sharp-Edge Add-Drop Filters Using Complementary-Misalignment-Modulated Grating-Assisted Contradirectional Couplers

Cited by 8 publications

References 20 publications

On‐Chip Metamaterial Enabled Wavelength (De)Multiplexer

On‐Chip Metamaterial Enabled Wavelength (De)Multiplexer

Subwavelength Grating‐Assisted Contra‐Directional Couplers in Lithium Niobate on Insulator

Electro-optic tunable grating-assisted optical waveguide directional coupler in lithium niobate

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