Computational Reanalysis of Optical Mode Localization in Fiber-Coupled Ring Resonators Using Temperature-Dependent Temporal Coupled-Mode Theory

Abstract

This preprint presents a computational reanalysis of optical mode localization in fiber-coupled ring resonators using a temperature-dependent Temporal Coupled-Mode Theory (TCMT) framework. The study investigates publicly available experimental transmission spectra from weakly coupled fiber ring resonators and develops a quantitative model that connects temperature-induced resonance detuning with the experimentally measurable normalized amplitude difference (VAD). Unlike simplified localization approximations, the proposed approach evaluates the complete TCMT transmission response and extracts the sensitivity landscape as a function of the normalized coupling coefficient. The analysis identifies an optimal coupling regime near c≈0.5 for the investigated resonator system and provides a quantitative sensitivity enhancement estimate with uncertainty evaluation. Spectral line-shape characteristics are further examined using Fano and Lorentzian resonance models. Model selection is performed using Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC), supported by residual diagnostics and bootstrap Monte Carlo uncertainty analysis. The study provides a reproducible computational workflow, including processed spectral data, analysis scripts, and generated figures, enabling independent verification and further development of coupled-resonator optical sensing strategies. This work demonstrates how computational reanalysis of open experimental data can reveal new design insights for improving the sensitivity and optimization of photonic resonator sensors.