Octave-spanning supercontinuum generation in a CMOS-compatible thin Si3N4 waveguide coated with highly nonlinear TeO2

TL;DR

This paper demonstrates efficient octave-spanning supercontinuum generation in a CMOS-compatible thin Si3N4 waveguide coated with nonlinear TeO2, achieving broadband light with low peak power through enhanced nonlinearity and dispersion engineering.

Contribution

It introduces a novel hybrid TeO2-Si3N4 waveguide platform that enables broadband supercontinuum generation in a thinner, more stress-resistant waveguide with enhanced nonlinearity.

Findings

Achieved octave-spanning supercontinuum at 258 W peak power.

TeO2 coating increases waveguide nonlinearity by 2.5 times.

Numerical simulations match experimental results.

Abstract

Supercontinuum generation (SCG) is an important nonlinear optical process enabling broadband light sources for many applications, for which silicon nitride(Si3N4) has emerged as a leading on-chip platform.To achieve suitable group velocity dispersion and high confinement for broadband SCG the Si3N4 waveguide layer used is typically thick (>~700 nm), which can lead to high stress and cracks unless specialized processing steps are used. Here, we report on efficient octave spanning SCG in a thinner moderate-confinement 400-nm Si3N4 platform using a highly nonlinear tellurium oxide (TeO2) coating. An octave-spanning supercontinuum is achieved at a low peak power of 258 W using a 100-fs laser centered at 1565 nm. Our numerical simulations agree well with the experimental results showing an increase of waveguide's nonlinear parameter by a factor of 2.5 when coating the Si3N4 waveguide with TeO2 film. This work demonstrates highly efficient SCG via effective dispersion engineering and an enhanced nonlinearity in a CMOS-compatible hybrid TeO2-Si3N4 waveguides and a promising route to monolithically integrated nonlinear, linear, and active functionalities on a single silicon photonic chip.