High-efficiency generation in a short random fiber laser

Abstract

We demonstrate a high-efficiency random lasing in a 850-m span of a phosphosilicate fiber. Random distributed feedback owing to the Rayleigh backscattering in the fiber enables narrowband generation with the output power of up to 7.3 W at the Stokes wavelength λ S =1308 nm from 11 W of the pump power at λ P =1115 nm. The laser demonstrates unique generation efficiency. Near the generation threshold, more than 2 W of output power is generated from only 0.5W of pump power excess over the generation threshold. At high pump power, the quantum conversion efficiency defined as a ratio of generated and pump photons at the laser output exceeds 100%. It is explained by the fact that every pump photon is converted into the Stokes photon far from the output fiber end, while the Stokes photons have lower attenuation than the pump photons.

High Power Random Fiber Laser With Short Cavity Length: Theoretical and Experimental Investigations

“…However, the numerical study also revealed that in this configuration with short fiber length, the presence of a small reflection at fiber ends will significantly change the power distribution, lower the slope efficiency, reduce the second-order lasing threshold and appreciably deteriorate the power performance [26], [31]. Very recently, high power RFLs with short fiber length have been experimentally demonstrated [32], [33]. Vatnik et al utilized a 850 m long phosphosilicate fiber featuring a large Stokes shift and achieved 7.3 W of first-order random lasing operating at 1308 nm with 66% optical conversion efficiency [32].…”

Spatio-temporal intensity dynamics of passively mode-locked fiber laser

“…Similar measurements could help to reveal hidden periodicity in the cavity-less lasers, such as random distributed feedback fibre lasers 25,26. Such lasers share many generation properties with conventional Raman fibre laser including possibility to polarized output 27, high-efficiency generation, 28 multi-wavelength 29 and tunable 30 generation. What is more important temporal dynamics of such lasers is defined as well by multiple turbulent like four-wave mixing processes 31, 32 which make their temporal radiation looking almost stochastic.…”

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

“…Due to these advantages, attentions have been paid to their applications in fiber-optic sensing and communication [3]- [5]. Also, various aspects of RFL have been studied: RFL has been designed to be narrow bandwidth [6], multiwavelength [7], [8] wavelength-tunable [9], Manuscript high power [10]- [12] and generating high order Stokes waves [13], [14]. Besides, the concept of RFL can be further developed by using Brillouin gain instead of Raman gain [15].…”

“…Recently, some achievements about high power RFL were reported [10]- [12]. In Reference [10], near the 5.5W lasing threshold, more than 2W of output power is generated from only 0.5W of pump power excess over the threshold, and finally they obtained 7.3W output with 11W pump source, while the input-output curve is nonlinear. However, a linear output is generally preferred in most applications.…”