Open AccessUltra-compact optical 90° hybrid based on a wedge-shaped 2 × 4 MMI coupler and a 2 × 2 MMI coupler in silicon-on-insulator
Author(s) -
Wei Yang,
Mei Yin,
Yanping Li,
Xingjun Wang,
Ziyu Wang
Publication year - 2013
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.21.028423
Subject(s) - silicon on insulator , extinction ratio , optics , materials science , silicon , silicon photonics , optoelectronics , waveguide , wedge (geometry) , physics , wavelength
We propose an ultra-compact optical 90° hybrid with the smallest length of 107μm, consisting of a wedge-shaped 2 × 4 MMI coupler connected with a 2 × 2 MMI coupler using silicon nanowaveguide technology. Neither cascaded phase shifters nor waveguide crossings are attached to the proposed 90° hybrid in coherent receiving system. The proposed device is demonstrated on silicon-on-insulator (SOI) with 220nm thick top-silicon layer and 2μm thick buried oxide layer. A high performance of the proposed 90° hybrid is exhibited experimentally with a high extinction ratio larger than 20dB, an excess loss mostly less than 0.5dB, a common mode rejection ratio better than -20dB and phase deviation within the range of 5° over C-band spectral range.