Supercontinuum generation in high-index doped silica photonic integrated circuits under diverse pumping settings

TL;DR

This study investigates supercontinuum generation in high-index doped silica integrated waveguides, demonstrating broadband spectra under anomalous dispersion pumping and polarization effects, supported by experiments and simulations.

Contribution

It provides a comprehensive analysis of supercontinuum generation across different pumping wavelengths and polarization states in high-index doped silica waveguides, including new Raman gain insights.

Findings

Broad supercontinuum (700-2400 nm) achieved with anomalous dispersion pumping.

Narrower spectra observed in normal dispersion regime at 1000 nm.

Polarization significantly influences supercontinuum spectral characteristics.

Abstract

Recent advances in supercontinuum light generation have been remarkable, particularly in the context of highly nonlinear photonic integrated waveguides. In this study, we thoroughly investigate supercontinuum (SC) generation in high-index doped silica glass integrated waveguides, exploring various femtosecond pumping wavelengths and input polarization states. We demonstrate broadband SC generation spanning from 700 nm to 2400 nm when pumping within the anomalous dispersion regime at 1200 nm, 1300 nm, and 1550 nm. In contrast, pumping within the normal dispersion regime at 1000 nm results in narrower SC spectra, primarily due to coherent nonlinear effects such as self-phase modulation and optical wave breaking. Additionally, we examine the impact of TE/TM polarization modes on SC generation, shedding light on the polarization-dependent characteristics of the broadening process. Moreover, Raman scattering measurements reveal the emergence of two new peaks at 48.8 THz and 75.1 THz in the Raman gain curve. Our experimental results are supported by numerical simulations based on a generalized nonlinear Schrodinger equation that incorporates the new Raman gain contribution. Finally, relative intensity noise measurements conducted using the dispersive Fourier transform technique indicate excellent stability of the generated SC spectra.