The all-fiber cladding-pumped Yb-doped gain-switched laser

C Larsen,K E Mattsson,K P Hansen,O Bang

doi:10.1364/oe.22.001490

Abstract

Gain-switching is an alternative pulsing technique of fiber lasers, which is power scalable and has a low complexity. From a linear stability analysis of rate equations the relaxation oscillation period is derived and from it, the pulse duration is defined. Good agreement between the measured pulse duration and the theoretical prediction is found over a wide range of parameters. In particular we investigate the influence of an often present length of passive fiber in the cavity and show that it introduces a finite minimum in the achievable pulse duration. This minimum pulse duration is shown to occur at longer active fibers length with increased passive length of fiber in the cavity. The peak power is observed to depend linearly on the absorbed pump power and be independent of the passive fiber length. Given these conclusions, the pulse energy, duration, and peak power can be estimated with good precision.

Highlights

Gain-switching of fiber lasers has been established as an alternative pulsing method due to the simplicity and all-fiber integration [1,2,3,4]
We show that the peak power can not be increased by minimizing the pulse duration, if this is done by shortening of the active fiber
This study on cladding-pumped gain-switched fiber lasers is motivated by the power scalability and simplicity of such lasers

Summary

Introduction

Gain-switching of fiber lasers has been established as an alternative pulsing method due to the simplicity and all-fiber integration [1,2,3,4]. The output pulse energies are often in the microjoule range and with repetition rates spanning from a few kilohertz up to the megahertz range [2, 5]. These properties make the gain-switched fiber lasers interesting for many applications; directly or after single-stage amplification in high-power fiber amplifiers [1, 2, 6, 7]. Stable Gaussian-like nanosecond pulses can be produced by choosing the pump power and duration appropriately [9]

Methods

Discussion

Conclusion