Germanium-on-silicon waveguides for long-wave integrated photonics: ring resonance and thermo-optics

Germanium-on-silicon (GOS) represents the leading platform for foundry-based long-wave infrared photonic integrated circuits (LWIR PICs), due to its CMOS compatibility and absence of oxides. We describe ring resonance (Q-factors between 2x10(3) and 1x10(4)) and thermo-optic tunability in germanium-on-silicon waveguides throughout the long-wave-infrared. The ring resonances are characterized by Q-factors and couplings that agree with measurements of propagation loss (as low as 6 dB/cm) and simulations and are enabled by broadband edge coupling (12dB/facet over a 3 dB bandwidth of over 4 microns). We demonstrate the furthest into the infrared that ring resonators have been measured and show the potential of this platform for photonic integration and waveguide spectroscopy at wavelengths from 7 microns to beyond 11 microns.

Automated summary

Germanium-on-silicon (GOS) is the leading platform for foundry-based long-wave infrared photonic integrated circuits (LWIR PICs) due to its CMOS compatibility and lack of oxides. Ring resonances and thermo-optic tunability in germanium-on-silicon waveguides have been described, showing potential for photonic integration and waveguide spectroscopy across a wide range of infrared wavelengths.