Optimization of fiber-coupled laser-diode end-pumped lasers: influence of pump-beam quality

Author

Chen, Y.F. ; Liao, T.S. ; Kao, C.F. ; Huang, T.M. ; Lin, K.H. ; Wang, S.C.

Author_Institution

Precision Instrum. Dev. Center, Nat. Sci. Council, Hsinchu, Taiwan

Volume

32

Issue

11

fYear

1996

fDate

11/1/1996 12:00:00 AM

Firstpage

2010

Lastpage

2016

Abstract

A general model has been developed for the optimization of fiber-coupled laser-diode pumped lasers by including the effect of pump-beam quality into the mode-overlap integrals. The numerical results of the mode-overlap integrals have been fitted to an analytical function of pump spot size, laser mode size and the parameter β, which is in terms of laser-diode beam quality and properties of the active medium. This analytical function allowed us to obtain explicit formulae for the threshold pump power, the slope efficiency, and the optimum pump spot size. With these formulae, the optimum mode size and the maximum output efficiency can be easily calculated for arbitrary values of β and input power. From the numerical results, we obtained an analytical expression to relate the required input power and pump-beam quality to the desired output efficiency and properties of an active medium. The present model provides a straightforward procedure to design the laser resonator and the optical coupling system for optimization. To illustrate the utility of the present model, a Nd:YAG laser pumped by fiber-coupled laser diodes is considered and optimized

Keywords

brightness; integral equations; laser beams; laser cavity resonators; laser modes; laser theory; modelling; neodymium; optical design techniques; optical fibre couplers; optical pumping; optimisation; solid lasers; Nd:YAG laser; YAG:Nd; YAl5O12:Nd; active medium; analytical expression; fiber-coupled laser diodes; fiber-coupled laser-diode end-pumped laser optimisation; input power; laser mode size; laser models; laser resonator; laser-diode beam quality; maximum output efficiency; mode-overlap integrals; optical coupling system; optimum mode size; optimum pump spot size; output efficiency; pump spot size; pump-beam quality; slope efficiency; threshold pump power; Design optimization; Fiber lasers; Laser beams; Laser excitation; Laser modes; Optical coupling; Optical design; Optical resonators; Power system modeling; Pump lasers;

fLanguage

English

Journal_Title

Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

0018-9197

Type

jour

DOI

10.1109/3.541689

Filename

541689