Low-Threshold, High-Efficiency Random Fiber Laser With Linear Output

Abstract

In this letter, we numerically study and experimentally achieve a low-threshold, high-efficiency random fiber laser, featuring a linear output as well. The lasing cavity incorporates a section of standard single-mode fiber and a band-selective point reflector placed at the far end of the fiber. The numerical result indicates that most energy is further pushed toward the pump side comparing with the open cavity scheme, producing a high-efficiency output. Then, we analyze the dependence of threshold and slope efficiency on cavity length and pumping wavelength. Most importantly, shorter cavity length would yield higher efficiency, and for different pumping wavelengths, there will be different cavity lengths corresponding to the lowest lasing threshold. Finally, we deliberately choose the parameters and experimentally achieve an 1145-nm random fiber laser with 7.13-W output and >90% slope efficiency (with 10-W pump), while the slope efficiency is almost constant above the 2-W lasing threshold. This letter provides a comprehensive guideline for designing such random fiber lasers with tailored performance.

Ultrafast convergent power-balance model for Raman random fiber laser with half-open cavity

“…For the backward-pumped experiments, we apply the present model to the low-threshold and high-efficiency RRFL with a 60% reflectivitive fiber loop mirror [29]. The pump wavelength is set as 1090 nm, the corresponding 1st-order Stokes is 1145 nm, and the laser cavity uses 5 km standard single-mode fiber (SMF).…”

Generation of Narrow Modes in Random Raman Fiber Laser Based on Multimode Fiber

“…The utilization of long fiber cavities or auxiliary ring fiber cavities ensures sufficient integral optical feedback for laser generation [14,15] as well as for the self-injection locking of Er-doped fiber lasers [16] or semiconductor lasers [17], narrowing the short-term linewidth down to the sub-kHz level [18], as well as producing effective parametric generation [19]. Note that nonlinear interactions that are well above the threshold strongly influence this generation, removing any signs of narrow modes [20,21], though filtering may give narrower linewidths even in these regimes [22].…”

Spatial mode switchable fiber laser based on FM-FBG and random distributed feedback

“…The RFL has shown unique features including a modeless feature, a near Gaussian type spectrum, time stability beyond threshold etc [4][5][6][7]. Also, the capability of providing a single-transverse-mode profile and long distance signal delivery with little sensitivity to environmental disturbances has attracted interest in the application fields of sensing and communications [8][9][10][11].…”