Ultraefficient on‐Chip Supercontinuum Generation from Sign‐Alternating‐Dispersion Waveguides

Abstract

Fully integrated supercontinuum sources on‐chip are critical to enabling applications such as portable and mechanically stable medical imaging devices, chemical sensing, and light detection and ranging. However, the low efficiency of current supercontinuum generation schemes prevents full on‐chip integration. Herein, a scheme where the input energy requirements for integrated supercontinuum generation are drastically lowered by orders of magnitude is presented, for bandwidth generation of the order of 500–1000 nm. Through sign‐alternating dispersion in a CMOS‐compatible silicon nitride waveguide, an efficiency enhancement by factors reaching 2800 is achieved. It is shown that the pulse energy requirement for large‐bandwidth supercontinuum generation at high spectral power (e.g., 1/e level) is lowered from nanojoules to 6 picojoules. The lowered pulse energy requirements enable that chip‐integrated laser sources, such as mode‐locked heterogeneously or hybrid‐integrated diode lasers, can be used as a pump source, enabling fully integrated on‐chip high‐bandwidth supercontinuum sources.