Efficient frequency conversion in a degenerate $\chi^{(2)}$ microresonator

TL;DR

This paper demonstrates a highly efficient on-chip frequency conversion scheme in a microresonator using degenerate sum-frequency conversion with broad tunability, enabling advanced applications in communications and sensing.

Contribution

The authors introduce a novel phase matching scheme for degenerate sum-frequency conversion in microresonators that achieves high efficiency and broad bandwidth.

Findings

Achieved 42% photon-number conversion efficiency.

Demonstrated broad tuning bandwidth over 250 GHz.

Observed cascaded Pockels and Kerr nonlinear effects.

Abstract

Microresonators on a photonic chip could enhance nonlinear optics effects, thus are promising for realizing scalable high-efficiency frequency conversion devices. However, fulfilling phase matching conditions among multiple wavelengths remains a significant challenge. Here, we present a feasible scheme for degenerate sum-frequency conversion that only requires the two-mode phase matching condition. When the drive and the signal are both near resonance to the same telecom mode, an efficient on-chip photon-number conversion efficiency upto 42% was achieved, showing a broad tuning bandwidth over 250GHz. Furthermore, cascaded Pockels and Kerr nonlinear optical effects are observed, enabling the parametric amplification of the optical signal to a distinct wavelength in a single device. The scheme demonstrated in this work provides an alternative approach to realizing high-efficiency frequency conversion and is promising for future studies on communications, atom clocks, sensing, and imaging.