Ultralow‐Noise Single‐Frequency Fiber Laser and Application in High‐Resolution Fiber‐Optic Dynamic Strain Sensing. Issue 10 (2nd August 2022)

• Record Type: Journal Article
• Authors: Zhao, Qilai; Sun, Yuxin; Zeng, Chun; Lin, Wei; Yang, Changsheng; Feng, Zhouming; Zhou, Kaijun; Wei, Xiaoming; Gan, Jiulin; Zhang, Qinyuan; Yang, Zhongmin; Xu, Shanhui
• Is Part Of: Advanced photonics research. Volume 3:Issue 10(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-02
• Subjects: dynamic strain sensing -- fiber lasers -- single frequencies -- ultralow noises; Photonics -- Periodicals; 621.36505
• DOI: 10.1002/adpr.202200080
• Languages: English
• ISSNs: 2699-9293

Abstract

Abstract : A 1.5 μm ultralow‐noise single‐frequency fiber laser (SFFL) is realized based on a delay fiber phase‐locked method and the nonlinear amplification effect of a semiconductor optical amplifier (SOA). Via feedback locking of the phase jitter signal, the phase noise achieves the minimum value of −160 dB rad Hz −1/2 m −1 with a maximum reduction of 50 dB. Meanwhile, SOA reduces the intensity noise by a maximum of 65 dB, making it near the shot‐noise limit for frequencies above 40 kHz. To demonstrate this state‐of‐art SFFL with ultralow‐noise property, a high‐resolution fiber‐optic dynamic strain sensing based on a fiber‐based Michelson interferometer (FMI) is performed. As a result, the strain resolution reaches 26 fε Hz −1/2 in the 30–200 Hz band, which is improved by almost three orders of magnitude than that realized by a free‐running SFFL. To the best of the knowledge, this is the first time to achieve such a high‐resolution fiber‐optic dynamic strain sensor in the low‐frequency range utilizing the FMI system. This high‐resolution fiber‐optic strain sensing has promising applications in geophysics and biophotonics. Moreover, this ultralow‐noise SFFL is competitive for sophisticated applications, such as precise absolute distance measurement, quantum key distribution, and generating squeezed light. Abstract : An ultralow‐noise single‐frequency fiber laser is realized. The phase noise is near the thermal noise limit, and the relative intensity noise is close to the shot noise limit. Based on this state‐of‐art laser, a high‐resolution fiber‐optic dynamic strain sensing is demonstrated, and it breaks the resolution record in low‐frequency bands from 1 to 10 Hz.