Thin-film filter wavelength-stabilized, grating combined, high-brightness kW-class direct diode laser

Abstract

We report on kW-class dense wavelength beam combining of a laser diode module consisting of ten broad-area laser diode bars by using a novel multi-laser cavity approach based on a thin-film filter (TFF) as a dispersive optical element. The wavelength-stabilized output of the TFF cavity is beam combined upon a -1 order transmission grating. Hereby, a cylindrical telescope is used for linear dispersion-matching between the TFF and the combiner grating. On the basis of simulations of the resulting beam quality deterioration, we are able to optimize the cavity and the combiner setup for optimal beam quality preservation. We demonstrate a highly efficient direct diode laser with 1.1-kW output power and a symmetrical beam parameter product of about 6mm × mrad (95 % power content) in both beam axis.

650W dual-wavelength locked high brightness diode laser pump source

“…For a long time, the dense wavelength division multiplexing (DWDM) technology in wavelength combining has been mature and simple in structure. Multi spectral efficient beam combining [4] can be achieved through filters or gratings, and it is easier to integrate into the pump source. Therefore, according to the absorption spectrum of Yb 3+ ions in the fiber laser, selecting the appropriate target wavelength, and using VBG wavelength locking and narrowband filtering technology can effectively improve the brightness of the pump source.…”