Compact Brillouin devices through hybrid integration on silicon

Blair Morrison,David Marpaung,Arnan Mitchell,Yang Liu,Stephen J Madden,Benjamin J Eggleton,Atiyeh Zarifi,Khu Vu,Thach G Nguyen,Alvaro Casas-Bedoya,Duk-Yong Choi,Guanghui Ren

doi:10.1364/optica.4.000847

Abstract

A range of unique capabilities in optical and microwave signal processing and generation have been demonstrated using stimulated Brillouin scattering (SBS). The need to harness SBS in mass-manufacturable integrated circuits has led to a focus on silicon-based material platforms. Remarkable progress in silicon-based Brillouin waveguides has been made, but results have been hindered by nonlinear losses present at telecommunications wavelengths. Here, we report on a new approach to surpass this issue through the integration of a high Brillouin gain material, As2S3, onto a silicon-based chip. We fabricated a compact spiral device within a silicon circuit, achieving an order-of-magnitude improvement in Brillouin amplification. To establish the flexibility of this approach, we fabricated a ring resonator with free spectral range precisely matched to the Brillouin shift, enabling the first demonstration, to our knowledge, of Brillouin lasing in a planar integrated circuit. Combining active photonic components with the SBS devices shown here will enable the creation of compact, mass-manufacturable optical circuits with enhanced functionalities.

Highlights

Stimulated Brillouin Scattering (SBS) has recently emerged as an impressive tool for optical processing and radio-frequency (RF) photonics
To establish the flexibility of this approach, we fabricated a ring resonator with free spectral range precisely matched to the Brillouin shift, enabling the first demonstration of Brillouin lasing in a silicon integrated circuit
The desire to harness SBS optical processing in CMOS (Complementary metaloxide-semiconductor) compatible platforms has recently culminated in demonstrations of SBS in various silicon on insulator (SOI) device architectures[23,24,25,26]

Summary

Introduction

Stimulated Brillouin Scattering (SBS) has recently emerged as an impressive tool for optical processing and radio-frequency (RF) photonics. SBS is one of the strongest nonlinearities known to optics, and is capable of providing exponential gain over narrow bandwidths of the order of tens of megahertz. This narrowband amplitude response is accompanied with a strong dispersive response, capable of tailoring the phase or group delay of a counter propagating optical signal. The demonstration of 52 dB Brillouin gain[21] in centimeter length scale As2S3 rib waveguides proves that performance equivalent to kilometers of optical fiber is achievable in integrated devices. In this work we introduce a hybrid integration approach to generate large Brillouin gain in a silicon-based device, free from nonlinear losses. This work marks a significant step towards the realisation of fully integrated active SBS devices, such as integrated opto-electronic oscillators[31] and lossless microwave photonic filters[32], in the near future

Methods

Results

Conclusion