Differential phase recovery from correlated long-baseline fiber interferometers using a DFB diode source
Year: 2026
Type: article
Abstract: We demonstrate real-time differential phase tracking between two correlated long-baseline interferometric systems where the coherence length of the optical source is significantly shorter than each individual interferometer arm mismatch. Using a 5 km Mach–Zehnder interferometer driven by a 100 kHz linewidth diode laser with a coherence length of ∼ 640 m, the coherent differential phase between the two interferometers is recovered without cycle-slip errors over the measurement period, despite the absence of individual phase coherence in either interferometer. We compare this with individual phasemeters, which experience multiple cycle-slip events in individual interferometer measurements and the computed differential, establishing a unique operating regime for interferometric sensing in which correlated measurements enable phase recovery in a regime where individual interferometer outputs are not independently trackable. We achieve a broadband differential phase noise floor of 10 −4 rad/Hz, and observe tunable signal fading effects related to fringe visibility reduction inversely proportional to the recovered signal bandwidth, and propose an initial model to describe this effect.
Source: Optics Express
DOI: 10.1364/oe.610791
Institution: Australian National University
Language: English
Topic: Advanced Fiber Optic Sensors
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
OpenAlex ID: W7220946177