Passively spatiotemporal gain-modulation-induced stable pulsing operation of a random fiber laser

Abstract

Unlike a traditional fiber laser with a defined resonant cavity, a random fiber laser (RFL), whose operation is based on distributed feedback and gain via Rayleigh scattering (RS) and stimulated Raman scattering in a long passive fiber, has fundamental scientific challenges in pulsing operation for its remarkable cavity-free feature. For the time being, stable pulsed RFL utilizing a passive method has not been reported. Here, we propose and experimentally realize the passive spatiotemporal gain-modulation-induced stable pulsing operation of counterpumped RFL. Thanks to the good temporal stability of an employed pumping amplified spontaneous emission source and the superiority of this pulse generation scheme, a stable and regular pulse train can be obtained. Furthermore, the pump hysteresis and bistability phenomena with the generation of high-order Stokes light is presented, and the dynamics of pulsing operation is discussed after the theoretical investigation of the counterpumped RFL. This work extends our comprehension of temporal property of RFL and paves an effective novel avenue for the exploration of pulsed RFL with structural simplicity, low cost, and stable output.

Coherent Random Fiber Laser-Enabled Super-Resolution Spectroscopy

“…Random fiber lasers (RFLs), which confine the lateral propagation of light, combine the advantages of fiber lasers and RLs, such as low lasing threshold, continuous-wave pumping, directional output, and easy integration with fiber optic systems. − Over the past decade, research on RFLs has flourished, with remarkable advancements in speckle-free imaging, , spectral manipulation, , pulsed operation, , and high-power/high-efficiency applications. , Coherent feedback-based RFLs are supported by light localization in arrays of disordered reflectors (e.g., randomly distributed fiber Bragg grating (RD-FBG) arrays). − Due to the complex interference between eigenmodes introduced by multipoint feedback, such lasers usually suffer from intense mode competition. , The lasing spectrum of coherent RFLs is inherently unstable, providing self-modulated stochastic emission characteristics that are promising for super-resolution spectroscopy. − …”

“…Random fiber lasers (RFLs), which confine the lateral propagation of light, combine the advantages of fiber lasers and RLs, such as low lasing threshold, continuous-wave pumping, directional output, and easy integration with fiber optic systems. 19−23 Over the past decade, research on RFLs has flourished, with remarkable advancements in speckle-free imaging, 24,25 spectral manipulation, 26,27 pulsed operation, 28,29 and high-power/high-efficiency applications. 30,31 Coherent feedback-based RFLs are supported by light localization in arrays of disordered reflectors (e.g., randomly distributed fiber Bragg grating (RD-FBG) arrays).…”

High-peak-power random Yb-fiber laser with intracavity Raman-frequency comb generation

“…In 2015, we proposed using a low Q-value cavity and amplified SBS to generate high peak power pulses from a self-Q-switched thulium RFL [27] . Subsequently, several groups realized pulsing operation of such kind of RFLs and studied their rich nonlinear dynamics including four-wave mixing (FWM), cascaded stimulated Raman scattering (SRS), and supercontinuum generation [28][29][30][31] . However, the nonlinearity-based self-Q-switching of RFLs is still at an early stage and the achieved highest pulse peak power is only a few kilowatts.…”

In-band pumping avenue based high power superfluorescent fiber source with record power and near-diffraction-limited beam quality

“…Especially, the utilizations of high power SFSs in many fields, such as mid-infrared laser and supercontinuum generation [10,11] , random fiber laser, and Raman fiber laser pumping [12][13][14] and spectral beam combination [15] , have been demonstrated in recent years for its inherent unique incoherence and high temporal stability characteristics. Consequently, the performance scalability of high power SFS is extremely significant.…”