Silicon subwavelength grating-assisted asymmetric directional coupler around 2 μm and its applications

被引：8

作者：

Zhu, Danfeng ^{[1
]}

Ye, Han ^{[1
]}

Liu, Yumin ^{[1
]}

Li, Jing ^{[1
]}

Wang, Yanrong ^{[1
]}

Yu, Zhongyuan ^{[1
]}

机构：

[1] Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, Beijing 100876, Peoples R China

来源：

OPTICS AND LASER TECHNOLOGY | 2021年 / 136卷

基金：

中国国家自然科学基金;

关键词：

Asymmetric directional coupler; Subwavelength grating; Mode (de)multiplexing; Reciprocal optical diode; Optical splitter; 2 mu m waveband; RECIPROCAL OPTICAL DIODE; WAVE-GUIDE; SUPERCONTINUUM GENERATION; FIBER; TRANSMISSION; DESIGN;

D O I：

10.1016/j.optlastec.2020.106789

中图分类号：

O43 [光学];

学科分类号：

070207 ; 0803 ;

摘要：

We propose a silicon-based asymmetric directional coupler assisted by subwavelength grating anisotmpic metamaterial operating at the emerging 2 mu m waveband. The effective medium theory is utilized to explain the principle of the proposed structure. Three devices with mode-order conversions are presented. Firstly, TEO-to-TE1, TEO-to-TE2, and TEO-to-TE3 conversions with remarkably high transmittance (> -0.17 dB) and extremely high mode purity (>98.81%) are achieved at the central wavelength of 1985 nm. The fabrication tolerance analyses demonstrate reasonable robustness of the proposed structure. Secondly, such structure can realize a reciprocal optical diode with an exceedingly high contrast ratio (>34 dB) based on spatial symmetry breaking. Finally, we present a symmetric 3 dB mode converter and splitter just by adjusting the length of subwavelength grating and the gap of asymmetric directional coupler. The results reveal that the transmittances of both output ports approach -3 dB around 2 mu m and the transmittance difference remains below -10 dB above 40 nm within the waveband from 1.95 mu m to 2.05 mu m.

引用

页数：10

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[1] Fiber-chip grating coupler based on interleaved trenches with directionality exceeding 95% [J].