CW 50W/M^2 = 109 diode laser source by spectral beam combining based on a transmission grating

Jun Zhang,Hangyu Peng,Xihong Fu,Yun Liu,Guoqing Miao,Li Qin,Lijun Wang

doi:10.1364/oe.21.003627

Abstract

An external cavity structure based on the -1st transmission grating is introduced to spectral beam combining a 970 nm diode laser bar. A CW output power of 50.8 W, an electro-optical conversion efficiency of 45%, a spectral beam combining efficiency of 90.2% and a holistic M(2) value of 10.9 are achieved. This shows a way for a diode laser source with several KW power and diffraction-limited beam quality at the same time.

Highlights

For high power diode lasers, how to improve the beam quality is a key technology problem to be solved [1]
Huang et al obtained a continuous wavelength (CW) power of 30 W and Mx;y2 = 2 by spectral beam combining of a 970 nm slab-coupled optical wave-guide laser (SCOWL), which consisted of 100 emitters and beam quality of each emitter is about Mx;y2 = 1.1 [7]
We find it suitable for spectral beam combining and can solve those problems of the reflective grating

Summary

Introduction

For high power diode lasers, how to improve the beam quality is a key technology problem to be solved [1]. A −1st order fused silica transmission grating is usually used for pulse compression of high power pulse laser [11, 12], providing a CW damage threshold and high diffractive efficiency. We find it suitable for spectral beam combining and can solve those problems of the reflective grating. Both of the incidence angle and diffractive angle are allowed to equal to the Littrow angle of grating and provides a better diffractive efficiency. A CW power of 50.8 W, a holistic M2 of 10.9, an electro-optical conversion efficiency of 45%, a spectral beam combining efficiency of 90.2% and a spectrum span of 24.1 nm are demonstrated

T-SBC experimental setup

T-SBC experimental results and analysis

Findings

Conclusion