Research On Measurement Of Fiber Length Based On Mode-Locked Fiber Laser

Optical fiber is the best media in modern communication networks for its characteristics of low loss and wide frequency band. Precise measurement of optical fiber length is a fundamental technique in many areas, such as in optical communications and fiber-optic sensing networks.We generate the all-fiber mode-locked laser with the symmetric nonlinear optical loop mirror, which can act as the saturable absorber for mode-locking with nonlinear polarization rotation based on the random birefringence of the single-mode fiber. The mode-locked fiber laser has the all-fiber nature and can be stable for a long term.Since the transit time in cavity corresponding to the fundamental frequency is exactly linearly proportional to the cavity length of the mode-locked fiber laser, a novel simple method to measure the fiber length has been experimentally demonstrated using a mode-locked fiber laser configuration. Compared to presented methods, there is no dead zone in our method and no limitation in measuring fiber length over hundreds of kilometers due to low insertion loss and direct splicing into an all-fiber...