Ultra-Efficient On-Chip Supercontinuum Generation from Sign-Alternating-Dispersion Waveguides

TL;DR

This paper introduces a sign-alternating dispersion scheme in silicon nitride waveguides that drastically reduces energy requirements for on-chip supercontinuum generation, enabling fully integrated high-bandwidth sources.

Contribution

The authors demonstrate a novel dispersion engineering method that enhances efficiency by up to 3800 times, significantly lowering the energy needed for supercontinuum generation on-chip.

Findings

Efficiency enhancement factors up to 3800

Pulse energy reduced from nanojoules to picojoules

Enables use of integrated diode lasers as pump sources

Abstract

Fully integrated supercontinuum sources on-chip are critical to enabling applications such as portable and mechanically-stable medical imaging devices, chemical sensing and LiDAR. However, the low-efficiency of current supercontinuum generation schemes prevent full on-chip integration. In this letter, we present a scheme where the input energy requirements for integrated supercontinuum generation is drastically lowered by orders of magnitude, for bandwidth generation of the order of 500 to 1000 nm. Through sign-alternating the dispersion in a CMOS compatible silicon nitride waveguide, we achieve an efficiency enhancement by factors reaching 3800. We show that the pulse energy requirement for large bandwidth supercontinuum generation at high spectral energy (e.g., 1/e level) is lowered from nanojoules to 6 picojoules. The lowered pulse energy requirements enables 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.