Mid-infrared supercontinuum generation in a low-loss germanium-on-silicon waveguide

We experimentally demonstrate supercontinuum (SC) generation in a germanium-on-silicon waveguide. This waveguide exhibits propagation loss between 1.2 dB/cm and 1.35 dB/cm in the 3.6 mu m-4.5 mu m spectral region for both transverse electric (TE) and transverse magnetic (TM) polarizations. By pumping the waveguide with similar to 200 fs pulses at 4.6 mu m wavelength, we generate a mid-infrared (IR) SC spanning nearly an octave from 3.39 mu m to 6.02 mu m at the -40 dB level. Through numerical analysis of the evolution of the SC, we attribute the current limit to further extension into the mid-IR mainly to free-carrier absorption.

Automated summary

Supercontinuum generation in a germanium-on-silicon waveguide was experimentally demonstrated, producing a mid-infrared supercontinuum covering nearly an octave. Numerical analysis attributed the current limit to free-carrier absorption, restricting further extension into the mid-IR region.