High-power direct diode laser output by spectral beam combining

Abstract

We demonstrate a spectral beam combining scheme based on multiple mini-bar stacks, which have more diode laser combining elements, to increase the combined diode laser power and realize equal beam quality in both the fast and slow axes. A spectral beam combining diode laser output of 1130 W is achieved with an operating current of 75 A. When a 9.6 X de-magnifying telescope is introduced between the output mirror and the diffraction grating, to restrain cross-talk among diode laser emitters, a 710 W spectral beam combining diode laser output is achieved at the operating current of 70 A, and the beam quality on the fast and slow axes of the combined beam is about 7.5 mm mrad and 7.3 mm mrad respectively. The power reduction is caused by the existence of a couple resonator between the rear facet of the diode laser and the fast axis collimation lens, and it should be eliminated by using diode laser chips with higher front facet transmission efficiency and a fast axis collimation lens with lower residual reflectivity.

Vector Rayleigh Diffraction of High-Power Laser Diode Beam in Optical Communication

“…e intensity of LD beams can be investigated in two vertical planes. In the plane perpendicular to the junction (i.e., y � 0), as shown in Figure 1, the substitution of y � 0 into equation (19) yields…”

“…However, the output beam quality of LDs is relatively poor, such as astigmatism, high beam asymmetry, and large beam divergence [17][18][19], in many applications, and proper theoretical models are needed to precisely describe the optical field distribution of LDs. e problem of laser propagation is mainly dealt through paraxial approximation.…”

High-Efficiency Spectral-Beam-Combined 930nm Diode Laser Source*

“…[13−15] By combining three 970 nm stacks with 6 min bars, they realized a 1130 W cw output power with a spectral beam combining efficiency of 67.8%. [16] In this Letter, a 930 nm diode laser is used as a combining source and a transmission grating is used for combining, which is shown to improve SBC efficiency. Wavelength interval and span related to the focal lengths of the transform lenses are theoretically discussed and experimentally checked.…”