Phase Combining Strategies for Polarization-Independent Demodulation in a DAS Using Homodyne Detection with Delayed Self-Mixing in a Non-Stabilized Mach-Zehnder Interferometer

Almaz Demise, Fabrizio Di Pasquale, Yonas Muanenda

2025

Abstract

We investigate a suitable polarization diversity algorithm for mitigating polarization fading in phase demodulation in a φ-OTDR based on a delayed Mach-Zehnder interferometer (MZI) and a polarization-diversity 90-degree optical hybrid. The intermediate components of the signal are combined using four different strategies employing weighing factors calculated from the SNR of the in-phase component and visibility of backscattering amplitude in the slow and fast axes to suppress polarization fading in distributed dynamic phase measurements. We compare the algorithms in terms of suitability for suppressing fading and added computational times. The proposed technique uses a single compact amplifier at the source and employs delayed self-mixing in an unbalanced MZI, thereby relaxing the requirement of temperature and phase isolation in the receiver interferometer. Experimental results show that, while all combining strategies mitigate fading, the selection of higher SNR of the in-phase component at the far end yields the best results in terms of ease of computation and could accurately detect weak acoustic signals at the end of a 10-km sensing fiber with a frequency of 2 kHz in the presence of fading in a single polarization.

Paper Citation

in Harvard Style

Demise A., Di Pasquale F. and Muanenda Y. (2025). Phase Combining Strategies for Polarization-Independent Demodulation in a DAS Using Homodyne Detection with Delayed Self-Mixing in a Non-Stabilized Mach-Zehnder Interferometer. In Proceedings of the 13th International Conference on Photonics, Optics and Laser Technology - Volume 1: PHOTOPTICS; ISBN 978-989-758-736-8, SciTePress, pages 49-56. DOI: 10.5220/0013185000003902

in Bibtex Style

@conference{photoptics25,
author={Almaz Demise and Fabrizio Di Pasquale and Yonas Muanenda},
title={Phase Combining Strategies for Polarization-Independent Demodulation in a DAS Using Homodyne Detection with Delayed Self-Mixing in a Non-Stabilized Mach-Zehnder Interferometer},
booktitle={Proceedings of the 13th International Conference on Photonics, Optics and Laser Technology - Volume 1: PHOTOPTICS},
year={2025},
pages={49-56},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0013185000003902},
isbn={978-989-758-736-8},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 13th International Conference on Photonics, Optics and Laser Technology - Volume 1: PHOTOPTICS
TI - Phase Combining Strategies for Polarization-Independent Demodulation in a DAS Using Homodyne Detection with Delayed Self-Mixing in a Non-Stabilized Mach-Zehnder Interferometer
SN - 978-989-758-736-8
AU - Demise A.
AU - Di Pasquale F.
AU - Muanenda Y.
PY - 2025
SP - 49
EP - 56
DO - 10.5220/0013185000003902
PB - SciTePress