Compact and integrated TM-pass waveguide polarizer

Chyong-Hua Chen,Chia-Ho Tsai,Yeshaiahu Fainman,Uriel Levy,Lin Pang

doi:10.1364/opex.13.005347

Abstract

A novel integrated TM-pass waveguide polarizer with a subwavelength-wide slot is introduced and theoretically analyzed. With a proper design of the slot, the waveguide can be used as a single polarization waveguide to guide only TM polarization modes of the light signal. With 26 microm length of this TM-pass polarizer, our computer simulations predict the insertion loss of 0.54 dB for the TM polarization mode with the extinction ratio of 20.3 dB at the wavelength of 1.55 microm.

Highlights

Optical waveguide polarizers are essential components in integrated photonics, especially for devices and systems operating with a single polarization (SP) such as fiber-optic gyroscopes, electro-optic switching arrays, coherent optical communication modules and more
A good polarizer is characterized by low insertion loss and high extinction ratio
A schematic drawing of the proposed design is shown in Fig. 1 with L1 being the length of the mode converter, L being the length of the TM-like SP waveguide and d being the distance between the two parallel waveguides

Summary

Introduction

Optical waveguide polarizers are essential components in integrated photonics, especially for devices and systems operating with a single polarization (SP) such as fiber-optic gyroscopes, electro-optic switching arrays, coherent optical communication modules and more. Many types of waveguide polarizers have been realized over the years, including, for example, metal-clad waveguides [1,2,3,4] and birefringence waveguides [5,6], but only few of them are TM-pass types One class of such polarizers is based on using a metal-cladding layer with either a grating [7,8] or a nanocomposite structure [9] to absorb the propagating TE polarization wave. Devices based on deposition of birefringent materials or form birefringent multilayers have been proposed as well, where TE polarization is eliminated due to different TE and TM cutoff wavelengths [11,12]; but relatively long distance (usually several millimeters) is needed to achieve high extinction ratio. With integration of Y-branch mode-converted waveguides, a high extinction ratio and low loss TMpass polarizer is realized. The simulation results indicate that the extinction ratio of 20.3 dB and the insertion loss of 0.54 dB can be obtained with a device length of 26 μm at the wavelength of 1.55 μm

Design of a TM-pass waveguide polarizer

Conclusions