Platforms for integrated nonlinear optics compatible with silicon integrated circuits

TL;DR

This paper reviews recent advances in CMOS-compatible nonlinear optical platforms like Hydex glass and silicon nitride, highlighting their potential for integrated photonic applications despite silicon's limitations.

Contribution

It provides a comprehensive overview of alternative materials for nonlinear optics compatible with silicon photonics, emphasizing recent progress and future challenges.

Findings

Hydex glass and silicon nitride enable on-chip optical frequency combs

Amorphous silicon shows promising nonlinear optical properties

These platforms overcome silicon's two-photon absorption limitations

Abstract

Nonlinear photonic chips are capable of generating and processing signals all-optically with performance far superior to that possible electronically - particularly with respect to speed. Although silicon has been the leading platform for nonlinear optics, its high two-photon absorption at telecommunications wavelengths poses a fundamental limitation. We review recent progress in CMOS-compatible platforms for nonlinear optics, focusing on Hydex glass and silicon nitride and briefly discuss the promising new platform of amorphous silicon. These material systems have opened up many new capabilities such as on-chip optical frequency comb generation, ultrafast optical pulse generation and measurement. We highlight their potential future impact as well as the challenges to achieving practical solutions for many key applications.