Study on Silicon-Based Polarization Converter Using Asymmetric Slot Waveguide

Zejun ZHANG  Yasuhide TSUJI  Masashi EGUCHI  Chun-ping CHEN  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E103-C   No.11   pp.605-608
Publication Date: 2020/11/01
Publicized: 2020/05/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.2019ESS0002
Type of Manuscript: BRIEF PAPER
Category: 
Keyword: 
polarization converter,  slot waveguide,  finite difference time domain method,  

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Summary: 
A compact optical polarization converter (PC) based on slot waveguide has been proposed in this study. Utilizing the high refractive index contrast between a Si waveguide and SiO2 cladding on the silicon-on-insulator platform, the light beam can be strongly confined in a slot waveguide structure. The proposed PC consists of a square waveguide and an L-shape cover waveguide. Since the overall structure is symmetrically distributed along the axis rotated 45-degree from the horizontal direction, the optical axis of this PC lies in the direction with equi-angle from two orthogonally polarized modes of the input and output ends, which leads to a high polarization conversion efficiency (PCE). 3D FDTD simulation results illustrate that a TE-to-TM mode conversion is achieved with a device length of 8.2 µm, and the PCE exceeds 99.8%. The structural tolerance and wavelength dependence of the PC have also been discussed in detail.