Advances in Random Fiber Lasers and Their Sensing Application

Abstract

Compared with conventional laser, random laser (RL) has no resonant cavity, reducing the requirement of cavity design. In recent years, the random fiber laser (RFL), a novel kind of RL, has made great progress in theories and experiments. The RFL has a simpler structure, a more flexible design, and higher reliability. It has valuable applications for earth sciences, biological life sciences, and national defense security, due to these unique properties. This paper reviews the development of RFLs in the last decade, including their configurations based on various optical fibers and their output properties, especially the method of control. Moreover, we also introduce their applications in the optical fiber sensing system, which is a very important and practical orientation to study. Finally, this paper presents the prospects of RFLs.

Hybrid Raman-Erbium Random Fiber Laser with a Half Open Cavity Assisted by Artificially Controlled Backscattering Fiber Reflectors

“…At one of its ends, a 2.4 km length spool of DCF, acting as a distributed reflector and amplifying the randomly backscattered light was located. As aforementioned, the DCF provides additional Rayleigh scattering feedback for the RFL [2], inducing a significant reduction of the typical gain medium length [24]. At the opposite end of the RFL, a 3 dB optical coupler divides the optical signal reflected by the DCF into two different branches, using a single gain medium per wavelength [25].…”

“…In recent years, random fiber lasers (RFLs) have thoroughly shown valuable applications in many practical engineering requests such as remote sensing, communications, optical astronomy and biomedical images among others [1]. One of their main characteristics is that they do not have well-defined mirrors but distributed reflectors instead, their feedback depends on the scattering along the fiber [2]. Such optical fiber distributed reflectors using Rayleigh backscattering provide interesting properties in lasers.…”

Narrow Linewidth Half-Open-Cavity Random Laser Assisted by a Three-Grating Ring Resonator for Strain Detection

“…A narrow linewidth is beneficial to suppress frequency noise levels of fiber lasers and can further improve resolution in optical dynamic strain-sensing systems [ 1 , 2 , 3 ]. Random fiber lasers (RFLs) have a simple cavity configuration, low threshold, and good temporal coherence, and they are a promising alternative for narrow linewidth and low frequency noise fiber lasers [ 4 , 5 , 6 ]. Recently, RFLs have attracted considerable interest due to their unique emission characteristic and potential sensing application prospects [ 4 , 7 ].…”

Single Longitudinal Mode Lasers by Using Artificially Controlled Backscattering Erbium Doped Fibers

“…Due to the low Rayleigh backscattering coefficient of the single mode fiber (SMF), high pump power levels for Raman amplification were initially needed for the operation of all random fiber lasers by using Raman gain. Recently [5], artificially controlled backscattering (ACB) techniques that do not require Raman amplification or technical conditions and processes as complex as those required to fabricate, for example, random fiber gratings (RFG) [5] have been demonstrated. However, they can generate a distributed mirror using the random feedback from Rayleigh scattering [6].…”