Dual-comb spectroscopy with tailored spectral broadening in Si${}_3$N${}_4$ nanophotonics

Abstract

Si${}_3$N${}_4$ waveguides, pumped at 1550 nm, can provide spectrally smooth, broadband light for gas spectroscopy in the important 2 $\mu$m to 2.5 $\mu$m atmospheric water window, which is only partially accessible with silica-fiber based systems. By combining Er+:fiber frequency combs and supercontinuum generation in tailored Si${}_3$N${}_4$ waveguides, high signal-to-noise dual-comb spectroscopy (DCS) spanning 2 $\mu$m to 2.5 $\mu$m is demonstrated. Acquired broadband dual-comb spectra of CO and CO${}_2$ agree well with database line shape models and have a spectral-signal-to-noise as high as 48$/\sqrt{\mathrm{s}}$, showing that the high coherence between the two combs is retained in the Si${}_3$N${}_4$ supercontinuum generation. The DCS figure of merit is 6$\times 10^6/\sqrt{\mathrm{s}}$, equivalent to that of all-fiber DCS systems in the 1.6 $\mu$m band. Based on these results, future DCS can combine fiber comb technology with Si${}_3$N${}_4$ waveguides to access new spectral windows in a robust non-laboratory platform.

References in corpus (12)

• Mid-infrared frequency combs
• Photonic Damascene Process for Integrated High-Q Microresonator Based Nonlinear Photonics
• High Coherence Mid-Infrared Dual Comb Spectroscopy Spanning 2.6 to 5.2 microns
• Mid-infrared frequency comb generation with silicon nitride nano-photonic waveguides
• An octave spanning mid-infrared frequency comb generated in a silicon nanophotonic wire waveguide
• Ultra-broadband dual-comb spectroscopy across 1.0-1.9 μm
• Ultrabroadband supercontinuum generation and frequency-comb stabilization using on-chip waveguides with both cubic and quadratic nonlinearities
• Accurate frequency referencing for fieldable dual-comb spectroscopy
• Self-referenced frequency combs using high-efficiency silicon-nitride waveguides
• Mid-infrared frequency comb generation via cascaded quadratic nonlinearities in quasi-phase-matched waveguides
• Versatile silicon-waveguide supercontinuum for coherent mid-infrared spectroscopy
• Tunable, Stable Source of Femtosecond Pulses Near 2 μm via Supercontinuum of an Erbium Mode-Locked Laser

Cited by in corpus (4)

• High-yield wafer-scale fabrication of ultralow-loss, dispersion-engineered silicon nitride photonic circuits
• Nanophotonic supercontinuum based mid-infrared dual-comb spectroscopy
• Tunable dual-comb from an all-polarization-maintaining single-cavity dual-color Yb:fiber laser
• Single-cycle all-fiber frequency comb