Sensor interrogation technique with multi‐wavelength laser based microwave photonic filter

• Published in: Microwave and optical technology letters Vol. 63; no. 10; pp. 2523 - 2527
• Main Authors: Dai, Weiyu, Wang, Haoran, Fu, Hongyan
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.10.2021; Wiley Subscription Services, Inc
• Subjects: Amplification; Doped fibers; Erbium; Fiber lasers; fiber Mach‐Zehnder interferometer; Interrogation; Laser applications; laser sensing; Lasers; microwave photonic filter; Microwave photonics; Optical fibers; Questioning; Semiconductor optical amplifiers
• ISSN: 0895-2477; 1098-2760
• DOI: 10.1002/mop.32983

In this article, we have proposed and demonstrated a sensing interrogation scheme of microwave photonic filter (MPF) based on multi‐wavelength fiber laser (MWFL). A Mach‐Zehnder interferometer (FMZI) acts as the wavelength selective component in the laser cavity as well as the sensing element. An erbium doped fiber amplifier (EDFA) and a semiconductor optical amplifier (SOA) are employed as hybrid gain medium to suppress the homogeneous broadening of erbium doped fiber. The MWFL is employed as the optical source to implement the MPF together with a dispersive medium. The free spectrum range of interference pattern of the FMZI changes with the temperature variation, thus changing the central frequency of MPF's passbands. The sensitivities are −12.23 and 6.11 MHz/°C, respectively, when the sensing optical fiber with the length of 2.2 and 1.1 m are used.