Type of Non-reciprocity in Fiber Sagnac Interferometer Induced by Geometric Phases

TL;DR

This paper investigates a novel non-reciprocity in fiber Sagnac interferometers caused by geometric phases from continuous weak measurement, revealing a sudden phase transition with potential for high-precision sensing.

Contribution

It introduces a new type of non-reciprocity unrelated to previous physical effects, based on geometric phases, with implications for optical fiber sensor design.

Findings

Identifies a new non-reciprocity mechanism in fiber Sagnac interferometers.

Discovers a sudden phase transition phenomenon.

Suggests potential for enhanced high-precision sensing applications.

Abstract

The non-reciprocity of Sagnac interferometer provides ultra-high sensitivity for parameter estimation and offers a wide range of applications, especially for optical fiber sensing. In this work, we study a new type of non-reciprocity existed in optical fiber Sagnac interferometer where the polarization dependent loss is taken into consideration. In particular, this non-reciprocity is irrelevant to the physical effects that being considered in previous studies, which originates from the geometric phases induced by continuous-weak-measurement. In consequence, it has a unique phenomenon of sudden phase transition, which may open a new way for the future design of high precision optical fiber sensors.