High-brightness fiber-coupled diode module using dense wavelength beam combining technology based on single emitter for material processing and fiber amplifier pumping
Fiber-coupled diode modules have various applications in material processing and fiber laser pumping because of their high eﬀiciency and high reliability. Commercial fiber-coupled diode modules using spatial beam combining and polarization beam combining cannot be employed in high-brightness applications, for example metal cutting, which demands a laser power exceeding 1 kW with a BPP of a few mm*mrad. Dense wavelength beam combining (DWBC) technology showed the possibility of further scaling-up the output power of fiber-coupled diode modules while maintaining the same beam quality that allows for fiber-coupled diode modules to be used in high-brightness applications. The eﬀiciency, reliability, and brightness of fiber-coupled diode modules can be improved by using single emitters instead of laser diode bars as power sources in DWBC. Two types of high-brightness 100 µm/0.22 NA 2 kW fiber-coupled diode modules employing single-emitter-based DWBC technology, which have a wavelength range from 953 to 991 nm with 50% eﬀiciency and a narrower wavelength range with 48% eﬀiciency respectively, were developed for material processing and Raman fiber amplifier pumping. Furthermore, we combined 15 high-brightness 100 µm/0.22 NA 1.4 kW fiber-coupled diode modules into a 600 µm/0.22 NA fiber, achieving more than 22 kW at the output.