All-Fiber Laser-Self-Mixing Interferometer With Adjustable Injection Intensity for Remote Sensing of 40 km

In this article, we propose an all-fiber self-mixing velocimeter based on a DBR fiber laser with adjustable injection intensity for the first time, and theoretically and experimentally explore the behavior of fiber lasers in detecting non-cooperative target under different injection intensities. When the ultra-strong injection level is attained, the linewidth of the DBR fiber laser will be narrowed to about 10 kHz, thus extending the coherence distance of laser tremendously. Simultaneously, the intensity noise can be also significantly suppressed. The non-cooperative target velocity measurement with 40 km single-channel transmission distance has been successfully achieved. This velocimeter is shown to be of great significance in the field of remote sensing with simple and compact configuration, and adjustable dynamical monitoring range.