Enhanced spectral sensitivity of a chip-scale photonic-crystal slow-light interferometer

TL;DR

This paper demonstrates that integrating a dispersion-engineered slow-light photonic-crystal waveguide into a Mach-Zehnder interferometer significantly enhances its spectral sensitivity, promising advancements in optical metrology and compact spectrometers.

Contribution

The study experimentally shows a 20-fold increase in spectral sensitivity using slow-light photonic crystals in a fiber-based interferometer, establishing a new approach for high-resolution optical sensing.

Findings

20 times enhancement in spectral sensitivity

Spectral sensitivity increases linearly with group index

Potential for high-resolution compact spectrometers

Abstract

We experimentally demonstrate that the spectral sensitivity of a Mach-Zehnder (MZ) interferometer can be enhanced through structural slow light. We observe a 20 times enhancement by placing a dispersion-engineered-slow-light photonic-crystal waveguide in one arm of a fibre-based MZ interferometer. The spectral sensitivity of the interferometer increases roughly linearly with the group index, and we have quantified the resolution in terms of the spectral density of interference fringes. These results show promise for the use of slow-light methods for developing novel tools for optical metrology and, specifically, for compact high-resolution spectrometers.