Frequency comb from a microresonator with engineered spectrum

TL;DR

This paper demonstrates control over frequency comb generation in microresonators by engineering the spectrum, achieving broad spans with lower pump power, and varying comb spacing.

Contribution

It introduces a method to control the comb spacing in microresonators by adjusting linewidth and dispersion ratios, enabling tailored frequency combs.

Findings

Achieved combs with N=19 and N=1 spacing.

Generated over 200 nm span with low pump power.

Reduced pump power requirement by a factor of 10.

Abstract

We demonstrate that by varying the ratio between the linewidth and dispersion of a whispering gallery mode resonator we are able to control the number N of free spectral ranges separating the first generated comb sidebands from the pump. We observed combs with N=19 and N=1. For the comb with N=1 we have achieved a span of over 200 nm using a 0.4 mm MgF2 resonator with a pump of 50 mW, which is a factor of 10 lower than previously reported.