Design of a SiO2 top-cladding and compact polarization splitter-rotator based on a rib directional coupler

Jing Wang, Chinese Academy of Science, Purdue University, Birck Nanotechnology Center
Ben Niu, Purdue University, Birck Nanotechnology Center
Zhen Sheng, Chinese Academy of Sciences
Aimin Wu, Chinese Academy of Sciences
Xi Wang, Chinese Academy of Sciences
Minghao Qi, Purdue University, Birck Nanotechnology Center
Fuwan Gan, Chinese Academy of Sciences
Shichang Zou, Chinese Academy of Sciences

Date of this Version

2-24-2014

Abstract

A compact polarization splitter-rotator based on a silicon-on-insulator rib asymmetrical directional coupler with SiO2 top-cladding is proposed. Unlike previously reported PSRs which specifically required the top-cladding material to be different from the bottom cladding in order to break the symmetry of the waveguide cross-section, our proposed PSR has no such limitation on the top-cladding due to the horizontal asymmetry of the rib waveguide. In addition, the device is highly compact and has a total length as short as 24 mu m. Numerical simulation shows that a high conversion efficiency of similar to 97% is obtained at the wavelength of 1550 nm. With the width variation of +/- 15 nm and the gap variation of +/- 50 nm, the PSR still has high ER of 12 dB at the cross-port, showing large fabrication tolerance. This device can be cascaded to improve the performance at the through port and an example of a two-stage PSR is presented. The mode conversion between the strip waveguide and the rib waveguide is also discussed. (C) 2014 Optical Society of America

Discipline(s)

Nanoscience and Nanotechnology

 

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