Open AccessUltra-compact and efficient 1 × 2 mode converters based on rotatable direct-binary-search algorithm
Author(s) -
Hansi Ma,
Jie Huang,
Kaiwang Zhang,
Junbo Yang
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.392145
Subject(s) - materials science , optics , fabrication , insertion loss , binary number , converters , reflection loss , optoelectronics , algorithm , computer science , physics , power (physics) , medicine , alternative medicine , pathology , quantum mechanics , composite number , arithmetic , mathematics
In this paper, we innovatively demonstrate a rotatable direct-binary-search algorithm. Based on this unique inverse design method, the coupling region of nanophotonic device can be realized with multi-shape and multi-rotation pixels. In addition, the novel 1× 2 mode converters with multipurpose design goals on a 220 nm-thick top silicon-on-insulator platform are proposed by utilizing this enhanced algorithm, which can simultaneously achieve power splitting and mode conversion. By 3D fine difference time domain solutions, the 1 × 2 mode converter that converts TE 0 mode into TE 1 , with a footprint of 2.7 µm × 2.4 µm, exhibits the excess loss of 0.1 - 0.2 dB (TE 1 mode), crosstalk of lower than -20.6 dB (TE 0 mode) and reflection loss of lower than -19.5 dB (TE 0 mode) from 1500 nm to 1600 nm. The 1 × 2 mode converter that transforms TE 0 into TE 2 occupies the footprint of 3.6 µm × 3 µm. The excess loss is 0.3 - 0.4 dB (TE 2 mode) in the wavelength range of 1500 - 1600 nm. The crosstalks are lower than -17.5 dB (TE 1 mode) and -25.1 dB (TE 0 mode), and the reflection loss is lower than -18.3 dB (TE 0 mode). Besides, the fabrication tolerances caused by both expansion or contraction of etched pattern contour and round corner effect are also investigated.