Slow-light enhanced gain in active photonic crystal waveguides

TL;DR

This paper experimentally demonstrates that slow light can enhance the gain in active semiconductor photonic crystal waveguides, opening avenues for compact optical amplifiers and advanced photonic devices.

Contribution

It provides the first experimental validation of slow-light-induced gain enhancement in active photonic crystal waveguides, previously only predicted theoretically.

Findings

Slow light increases gain coefficient in active waveguides

Experimental demonstration of slow-light gain enhancement

Potential for ultra-compact integrated optical amplifiers

Abstract

Slow light is a fascinating physical effect, raising fundamental questions related to our understanding of light-matter interactions as well as offering new possibilities for photonic devices. From the first demonstrations of slow light propagation in ultra-cold atomic gasses, solid-state Ruby and photonic crystal structures, focus has shifted to applications, with slow light offering the ability to enhance and control light-matter interactions. The demonstration of tuneable delay lines, enhanced nonlinearities and spontaneous emission, enlarged spectral sensitivity and increased phase shifts illustrate the possibilities enabled by slow light propagation, with microwave photonics emerging as one of the promising applications. Here, we demonstrate that slow light can be used to control and increase the gain coefficient of an active semiconductor waveguide. The effect was theoretically predicted but not yet experimentally demonstrated. These results show a route towards realizing ultra-compact optical amplifiers for linear and nonlinear applications in integrated photonics and prompts further research into the rich physics of such structures.