Thermal Control of Transmission Spectral Characteristics in a Ring Resonator

TL;DR

This paper demonstrates how thermal tuning of a micro-ring resonator coupled with an etalon can dynamically modify spectral line shapes, enabling advanced control for optical communication and sensing applications.

Contribution

It introduces a method for thermally controlling the spectral line shapes of coupled resonators, including Fano and EIT-like features, which was not previously demonstrated.

Findings

Thermal tuning alters coupling strength and losses.

Spectral line shapes can be switched from symmetric to asymmetric.

Potential applications in optical switches and sensors.

Abstract

We report on our observation of thermal control of transmission spectra of a micro-ring resonator coupled to a low finesse etalon. Thermal tuning of the device changes the coupling strength and losses between the etalon and ring resonator resulting in a wide variety of line shapes ranging from a symmetric to asymmetric Fano-like to electromagnetically induced transparency (EIT)-like behavior. The capability to modify spectral line shapes by thermally tuning the coupling strength and losses between two resonators has obvious applications in optical communication networks and relevance to sensor applications where it may be exploited for developing novel cutoff switches and has significant, deleterious effect on measurement uncertainties of large dynamic range sensors.