Efficient Frequency Conversion in a Degenerate χ(2) Microresonator

Microresonators on a photonic chip could enhance nonlinear optics effects and 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 on-chip photon-number conversion efficiency up to 42% is achieved, showing a broad tuning bandwidth over 250 GHz. Furthermore, cascaded Pockels and Kerr nonlinear optical effects are observed, enabling the parametric amplification of the optical signal to distinct wavelengths in a single device. The scheme demonstrated in this Letter provides an alternative approach to realizing high-efficiency frequency conversion and is promising for future studies on communications, atom clocks, sensing, and imaging.

Automated summary

This study presents a feasible scheme for degenerate sum-frequency conversion that achieves high-efficiency frequency conversion by only requiring the two-mode phase matching condition. When both the drive and signal are near resonance to the same telecom mode, an on-chip photon-number conversion efficiency of up to 42% is achieved, with a tuning bandwidth over 250 GHz. Furthermore, cascaded Pockels and Kerr nonlinear optical effects enable parametric amplification of the optical signal to distinct wavelengths in a single device.