Low Loss Electro-Optic Polymer Based Fast Adaptive Phase Shifters Realized in Silicon Nitride and Oxynitride Waveguide Technology

Lars Baudzus,Peter Krummrich

doi:10.3390/photonics3030049

Abstract

We present a comprehensive study on how to design and fabricate low loss electro-optic phase shifters based on an electro-optic polymer and the silicon nitride and silicon oxynitride waveguide material systems. The loss mechanisms of phase shifters with an electro-optic (EO) polymer cladding are analyzed in detail and design solutions to achieve lowest losses are presented. In order to verify the low loss design a proof of concept prototype phase shifter was fabricated, which exhibits an attenuation of 0.8 dB/cm at 1550 nm and an electro-optic efficiency factor of 27%. Furthermore, the potential of this class of phase shifters is evaluated in numerical simulations, from which the optimal design parameters and achievable figures of merit were derived. The presented phase shifter design has its potential for application in fast adaptive multi stage devices for optical signal processing.

Highlights

Equalization enhances the robustness of data transmissions at high data rates in optical communication systems
That the silicon oxynitride (SiON) and silicon nitride (SiN) material systems can be combined with EO polymers to realize fast adaptive phase shifters with a very low attenuation
In numerical simulations a set of design parameters could be determined, which optimizes the losses per phase shifter for a given driving voltage

Summary

Introduction

Equalization enhances the robustness of data transmissions at high data rates in optical communication systems. It can be performed by digital signal processing, and by optical signal processing [1,2]. An optical equalizer can be implemented as an integrated optical filter, whose properties are adaptable by optical phase shifters. A low optical attenuation is important to prevent excessive losses due to multiple stages in an optical equalizer. These requirements can be met by phase shifters based on the electro-optic (EO) effect. Phase shifters based on the thermo-optic effect are less power efficient and liquid crystals have typically a response time, which is too slow for their application in optical equalizers with real-time control

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