All-Optical High-Resolution Real-Time Temperature Estimation Method Based on Fiber-Optic Interferometry

TL;DR

This paper introduces an EKF-based method for fiber-optic interferometry that significantly improves real-time temperature measurement resolution and robustness against environmental disturbances.

Contribution

The authors develop a novel EKF-based approach that accounts for non-linearity and noise, achieving high-resolution, real-time temperature estimation with enhanced immunity to disturbances.

Findings

Estimation error reduced to 2.21e-5 K in simulations.

Experimental resolution achieved is 8.34e-5 K under disturbances.

Threefold improvement over conventional intensity-based methods.

Abstract

High-resolution temperature monitoring is essential for many engineering and scientific applications, but conventional sensors are limited by insufficient resolution and susceptibility to electromagnetic interference. Fiber-optic interferometers provide high sensitivity and intrinsic electromagnetic immunity; however, their practical performance is hindered by nonlinear temperature-intensity responses, phase ambiguity, and environmental disturbances. Here, we develop an extended Kalman filter (EKF)-based approach that incorporates system non-linearity and noise statistics to enable robust real-time temperature estimation from interferometric signals. In numerical simulations, our EKF-based method reduces the estimation error to 2.21e-5 K, while experiments achieve a resolution of 8.34e-5 K under strong disturbances, corresponding to a threefold improvement over conventional intensity-based inversion method and an order-of-magnitude enhancement compared with traditional based measurement. These results demonstrate a compact and robust strategy for high-resolution, real-time, all-optical temperature sensing with strong immunity to electromagnetic interference.