All-Fibre Comb Filter with Narrow Bandwidth Based on a Dual-Pass Mach-Zehnder Interferometer

Li Wei

2025

Abstract

A theoretical analysis of an all-fibre comb filter with narrow bandwidth is presented, based on a dual-pass Mach-Zehnder interferometer (DP-MZI) with two variable ratio couplers. While the DP-MZI has previously been used to construct a flattop comb filter via the reflection port, in this work it is employed as a narrow bandwidth comb filter through the transmission port. Two conditions are newly derived to determine how to choose the coupling ratios to optimize the optical performance of the proposed comb filter. First, to obtain a lossless narrow-bandwidth filter, the coupling ratios of the two couplers must be equal. Second, to achieve maximum extinction ratio, these coupling ratios are equal to 0.146 or 0.854. The impact of the coupling ratios on bandwidth and extinction ratio is investigated. It is shown that the 3-dB bandwidth can be further reduced by tuning the coupler ratios near the optimal value. This unique property is highly desirable for applications in fibre lasers, optical sensing technology and reconfigurable optical systems.

Paper Citation

in Harvard Style

Wei L. (2025). All-Fibre Comb Filter with Narrow Bandwidth Based on a Dual-Pass 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 87-91. DOI: 10.5220/0013144300003902

in Bibtex Style

@conference{photoptics25,
author={Li Wei},
title={All-Fibre Comb Filter with Narrow Bandwidth Based on a Dual-Pass Mach-Zehnder Interferometer},
booktitle={Proceedings of the 13th International Conference on Photonics, Optics and Laser Technology - Volume 1: PHOTOPTICS},
year={2025},
pages={87-91},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0013144300003902},
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 - All-Fibre Comb Filter with Narrow Bandwidth Based on a Dual-Pass Mach-Zehnder Interferometer
SN - 978-989-758-736-8
AU - Wei L.
PY - 2025
SP - 87
EP - 91
DO - 10.5220/0013144300003902
PB - SciTePress