Temperature Dependence of a Depth-Encoded System for Polarization-Sensitive Optical Coherence Tomography using a PM Fiber

TL;DR

This paper investigates how temperature variations impact a depth-encoded polarization-sensitive OCT system using a PM fiber, affecting delay, dispersion, and resolution, and discusses mitigation via complex master/slave interferometry.

Contribution

It characterizes temperature effects on a depth-encoded PS-OCT system and explores mitigation strategies to improve stability and resolution.

Findings

Temperature influences delay and dispersion in the system.

Temperature instability affects axial resolution.

CMSI can mitigate temperature-induced effects.

Abstract

A polarization-sensitive optical coherence tomography (PS-OCT) system is able to not only show the structure of samples through the analysis of backscattered light, but is also capable of determining their polarimetric properties. This is an extra functionality to OCT which allows the retardance and axis orientation of a bulk sample to be determined. Here, we describe the temperature instabilities of a depth-encoded, multiple input state PS-OCT system, where two waves corresponding to two orthogonal states in the interrogating beam are delayed using a 5-meter long polarization-maintaning (PM) fiber. It is shown that the temperature not only affects the delay between the two relatively delayed waves, but also the amount of mismatched dispersion in the interferometer, which ultimately affects the achievable axial resolution in the system. To this end, the technique of complex master/slave interferometry (CMSI) can be used as an option to mitigate this effect.