Tunable mid-infrared generation via wide-band four wave mixing in silicon nitride waveguides

TL;DR

This paper demonstrates wide-band mid-infrared generation through four-wave mixing in silicon nitride waveguides, enabling tunable MIR output and broadband parametric gain from fiber-based pulses on a chip.

Contribution

It introduces a novel integrated photonic approach for tunable MIR generation and broadband amplification using engineered dispersion in silicon nitride waveguides.

Findings

Tunable MIR from 2.6-3.6 μm achieved on a chip.

Over 20 dB broadband parametric gain observed.

Wide-band frequency down-conversion of NIR pulses demonstrated.

Abstract

We experimentally demonstrate wide-band (>100 THz) frequency down-conversion of near-infrared (NIR) femtosecond-scale pulses from an Er:fiber laser to the mid-infrared (MIR) using four-wave-mixing (FWM) in photonic-chip silicon-nitride waveguides. The engineered dispersion in the nanophotonic geometry, along with the wide transparency range of silicon nitride, enables large-detuning FWM phase-matching and results in tunable MIR from 2.6-3.6 um on a single chip with 100-pJ-scale pump-pulse energies. Additionally, we observe > 20 dB broadband parametric gain for the NIR pulses when the FWM process is operated in a frequency up-conversion configuration. Our results demonstrate how integrated photonic circuits could realize multiple nonlinear optical phenomena on the same chip and lead to engineered synthesis of broadband, tunable, and coherent light across the NIR and MIR wavelength bands from fiber-based pumps.