Experimental realization of an O-band compact polarization splitter and rotator

Kang Tan,Ying Huang,Guo-Qiang Lo,Changyuan Yu,Chengkuo Lee

doi:10.1364/oe.25.003234

Abstract

We experimentally realize a compact wideband polarization splitter and rotator (PSR) with CMOS compatibility. The fabricated PSR is then tested by utilizing a fabrication-tolerant TE-pass on-chip polarizer we propose to practically solve the issue of accurately aligning the polarizations in fiber and modes on chip. Both of these polarization handling devices take the advantage of bend structure that confines TE mode better than TM mode. The fabricated PSR has a high TM-TE and TE-TE mode conversion efficiency of -0.4 dB and -0.2 dB at 1310 nm, while the extinction ratio is better than 18 dB and the broad bandwidth exceeds 100 nm.

Highlights

Silicon photonics provide the possibility of designing and fabricating ultra-compact and CMOS-compatible photonic building blocks with low manufacturing cost, which creates an expanding market, especially for current data center applications [1,2]
Different design for polarization splitter and rotator (PSR) have been proposed, including directional coupler (DC) [5,6,7], adiabatic tapers followed by Mach-Zehnder interferometer [8, 9], mode-evolution tapers followed by asymmetric Yjunction [10], slot waveguide [11], etc
We experimentally realize an O-band CMOS-compatible PSR utilizing ultracompact double bends with a radius of 10 μm, which is measured with the assistance of a fabrication-tolerant TE-pass on-chip polarizer we propose for accurately aligning the polarization in fiber and modes on chip

Summary

Introduction

Silicon photonics provide the possibility of designing and fabricating ultra-compact and CMOS-compatible photonic building blocks with low manufacturing cost, which creates an expanding market, especially for current data center applications [1,2]. We experimentally realize an O-band CMOS-compatible PSR utilizing ultracompact double bends with a radius of 10 μm, which is measured with the assistance of a fabrication-tolerant TE-pass on-chip polarizer we propose for accurately aligning the polarization in fiber and modes on chip. We further explore the advantage brought by bend and design a multi-bend structure naturally functioned as an on-chip fabrication-tolerant TE-pass polarizer, which provides a practical solution for accurately aligning the polarizations in fiber and modes on chip. After setting the free space polarizer 2 to allow TE mode to pass through, we roughly rotate the input lensed fiber to minimize the output power collected by NIR camera, which means the injected light is roughly aligned to TM mode for silicon chip. The CEs for the stimulated TM and TE mode are defined as ( )

Input TM

Conclusion