All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder Interferometer

An all-optical single-longitudinal-mode (SLM) forward Brillouin microwave oscillator (FB-MO) with an unbalanced Fiber Mach–Zehnder interferometer (UF-MZI) for microwave photonics (MWP) generation is proposed and experimentally investigated. UF-MZI consists of an optical coupler (OC), a polarization...

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Main Authors: Xinyue Fang, Wenjun He, Wen Wang, Yi Liu, Yajun You, Qing Yan, Yafei Hou, Zepeng Wu, Lei Yu, Songquan Yan, Mingxing Li, Jian He, Xiujian Chou
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Micromachines
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Online Access:https://www.mdpi.com/2072-666X/16/2/209
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author Xinyue Fang
Wenjun He
Wen Wang
Yi Liu
Yajun You
Qing Yan
Yafei Hou
Zepeng Wu
Lei Yu
Songquan Yan
Mingxing Li
Jian He
Xiujian Chou
author_facet Xinyue Fang
Wenjun He
Wen Wang
Yi Liu
Yajun You
Qing Yan
Yafei Hou
Zepeng Wu
Lei Yu
Songquan Yan
Mingxing Li
Jian He
Xiujian Chou
author_sort Xinyue Fang
collection DOAJ
description An all-optical single-longitudinal-mode (SLM) forward Brillouin microwave oscillator (FB-MO) with an unbalanced Fiber Mach–Zehnder interferometer (UF-MZI) for microwave photonics (MWP) generation is proposed and experimentally investigated. UF-MZI consists of an optical coupler (OC), a polarization controller (PC), and two asymmetric length arms with 5 km and 500 m single-mode fibers (SMFs), which implements two unbalanced length feedback rings that are connected to one another. One long-length ring with a forward Brillouin gain cooperates with the other short-length ring to maintain a spectral Vernier effect and improve the effective free spectral range (FSR). By contrast with traditional optoelectronic oscillators (OEOs), this design does not require any photoelectric conversion devices and additional modulation, avoids external electromagnetic interference, and side-mode suppression and linewidth are favorable. Experimental results reveal that the 3-dB linewidth of the all-optical SLM FB-MO with UF-MZI is about 140 Hz. The acoustic-mode and side-mode suppression ratios are 26 dB and 31 dB. Within 60 min of the stability experiment, the power and frequency stability fluctuation were ±1 dB and ±100 Hz. Thanks to its long main ring cavity length, our all-optical SLM FB-MO with UF-MZI maintains good phase-noise performance. The measurement shows that a phase noise as low as −120 dBc/Hz at an offset frequency of 100 kHz is achieved. This SLM MWP generation technology holds great potential for applications in radar monitoring and wireless communication systems.
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spelling doaj-art-6e46c92b5f28452daa5e43ef62d3a5a02025-08-20T03:12:22ZengMDPI AGMicromachines2072-666X2025-02-0116220910.3390/mi16020209All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder InterferometerXinyue Fang0Wenjun He1Wen Wang2Yi Liu3Yajun You4Qing Yan5Yafei Hou6Zepeng Wu7Lei Yu8Songquan Yan9Mingxing Li10Jian He11Xiujian Chou12State Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaShanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaState Key Laboratory of Dynamic Measurement Technology, School of Instrument and Electronics, North University of China, Taiyuan 030051, ChinaAn all-optical single-longitudinal-mode (SLM) forward Brillouin microwave oscillator (FB-MO) with an unbalanced Fiber Mach–Zehnder interferometer (UF-MZI) for microwave photonics (MWP) generation is proposed and experimentally investigated. UF-MZI consists of an optical coupler (OC), a polarization controller (PC), and two asymmetric length arms with 5 km and 500 m single-mode fibers (SMFs), which implements two unbalanced length feedback rings that are connected to one another. One long-length ring with a forward Brillouin gain cooperates with the other short-length ring to maintain a spectral Vernier effect and improve the effective free spectral range (FSR). By contrast with traditional optoelectronic oscillators (OEOs), this design does not require any photoelectric conversion devices and additional modulation, avoids external electromagnetic interference, and side-mode suppression and linewidth are favorable. Experimental results reveal that the 3-dB linewidth of the all-optical SLM FB-MO with UF-MZI is about 140 Hz. The acoustic-mode and side-mode suppression ratios are 26 dB and 31 dB. Within 60 min of the stability experiment, the power and frequency stability fluctuation were ±1 dB and ±100 Hz. Thanks to its long main ring cavity length, our all-optical SLM FB-MO with UF-MZI maintains good phase-noise performance. The measurement shows that a phase noise as low as −120 dBc/Hz at an offset frequency of 100 kHz is achieved. This SLM MWP generation technology holds great potential for applications in radar monitoring and wireless communication systems.https://www.mdpi.com/2072-666X/16/2/209single-longitudinal-modeforward BrillouinMach–Zehnder interferometer
spellingShingle Xinyue Fang
Wenjun He
Wen Wang
Yi Liu
Yajun You
Qing Yan
Yafei Hou
Zepeng Wu
Lei Yu
Songquan Yan
Mingxing Li
Jian He
Xiujian Chou
All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder Interferometer
Micromachines
single-longitudinal-mode
forward Brillouin
Mach–Zehnder interferometer
title All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder Interferometer
title_full All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder Interferometer
title_fullStr All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder Interferometer
title_full_unstemmed All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder Interferometer
title_short All-Optical Single-Longitudinal-Mode Forward Brillouin Microwave Oscillator with an Unbalanced Fiber Mach–Zehnder Interferometer
title_sort all optical single longitudinal mode forward brillouin microwave oscillator with an unbalanced fiber mach zehnder interferometer
topic single-longitudinal-mode
forward Brillouin
Mach–Zehnder interferometer
url https://www.mdpi.com/2072-666X/16/2/209
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