Experimental and theoretical study of longitudinal power distribution in a random DFB fiber laser

Dmitry V Churkin,Sergei K Turitsyn,Paul Harper,Juan Diego Ania-Castañón,Ilya D Vatnik,Sergey A Babin,Atalla E El-Taher,Eugeny V Podivilov

doi:10.1364/oe.20.011178

Abstract

We have measured the longitudinal power distribution inside a random distributed feedback Raman fiber laser. The observed distribution has a sharp maximum whose position depends on pump power. The spatial distribution profiles are different for the first and the second Stokes waves. Both analytic solution and results of direct numerical modeling are in excellent agreement with experimental observations.

Highlights

The novel concept of a fiber laser operating via the feedback produced by randomly distributed variations of refractive index in the fiber core was proposed and implemented [1]
The lasing mechanism in such random distributed feedback (DFB) fiber laser is similar to the one seen in random lasers where light is generated in an amplifying disordered medium without a traditional cavity
For pump power above ~2 W, the second Stokes wave (~1.68 μm) is generated similar to the cascaded generation observed in random DFB fiber laser operating in the 1.2 μm spectral band [9]

Summary

Introduction

The novel concept of a fiber laser operating via the feedback produced by randomly distributed variations of refractive index in the fiber core was proposed and implemented [1]. Since its output power is defined by the specific longitudinal distribution of the generated power along the fiber, further optimization is possible while taking into account the shape of the distribution Another important issue is that the random DFB laser has no limit in length in contrast to ultra-long Raman fiber lasers with conventional cavity of point-action reflectors, namely fiber Bragg gratings (FBGs) [13]. Ultra-long random DFB fiber lasers could be longer than conventional ultra-long Raman fiber lasers enabling quasi-lossless transmission over greater distances For such telecommunication applications, the study of longitudinal distribution of generated power is one of the key issues

Methods

Results

Conclusion