Tri-layer SiN-on-Si 8x8 Optical Switches with Thermo-optic and Electro-optic Actuators

TL;DR

This paper introduces innovative 8x8 optical switches on a tri-layer SiN-on-Si platform, utilizing thermo-optic and electro-optic actuators, achieving low crosstalk and fast switching suitable for data centers.

Contribution

First demonstration of electro-optic switch fabric in a multi-layer SiN-on-Si platform with a 3D photonic shuffle network and suppressed crosstalk.

Findings

On-chip losses: 2.1-11.5 dB (T-O), 8.7-19.6 dB (E-O)

Crosstalk: 38.9-50.8 dB (T-O), 42.8-51.9 dB (E-O)

Switching times: 17.6 us (T-O), 5.9 ns (E-O)

Abstract

We present two spatial-multiplexed switch-and-select (S&S) 8x8 optical switches incorporating a tri-layer SiN-on-Si platform, one equipped with thermo-optic (T-O) and the other electro-optic (E-O) switching elements. To the best of our knowledge, the electro-optic switch fabric is the first-of-its-kind device assembled in such a multi-layer platform. The shuffle between the multiplexer and demultiplexer array is established via a tri-layer Si-SiN-SiN structure, creating a three-dimensional crossing-free photonic shuffle network. At the same time, the implementation of the S&S topology can effectively suppress the first-order crosstalk. The measured on-chip losses for the T-O switch range from 2.1 to 11.5 dB, with a 5.2 dB average, while the E-O device exhibits losses between 8.7 to 19.6 dB, with a 15.1 dB average. Both switches demonstrate ultra-low crosstalk, with measured ranges of 38.9 to 50.8 dB and 42.8 to 51.9 dB, for the T-O and E-O devices respectively. The switching times are 17.6 us for the T-O switch and 5.9 ns with the E-O actuated one. These performance metrics highlight the potential of these switches for next-generation data center applications.