High-Brightness Fiber-Coupled Pump Modules Utilizing Robust Mini-Bar Technology Pump Devices

摘要

High-brightness multimode, multi-element diode-laser pump modules are considered by many as an ideal source for both fiber-laser pumping, end-face pumping, as well as direct diode applications [1, 2]. Single component pump module powers in excess of 25 W, within a 200-micron multimode fiber 0.20 numerical aperture (NA) core result in a brightness of 0.5 MW/cm~2-Sr. When wavelength targeted at an absorption peak of Nd:YAG these devices can become of particular interest. Multiple modules, with the coupling of commercially available tapered fiber combiners, are combined to generate high-power pump trays. In this work, 19 individual pump modules averaging 27 W of optical power and 43% electrical to optical power conversion efficiency are optically combined through a 19:1 fiber combiner and targeted at 879 nm. The result is an output power of 500 W in a single 400-micron 0.46-NA fiber. Electrical and optical performance of the fiber tray is shown in Fig. 1. This is achieved while maintaining a narrow spectral bandwidth suitable for the absorption width at the Nd:YAG target wavelength of interest. In this work we detail the packaging of such a device and demonstrate a combined overall 41% wall-plug efficiency and combined bandwidth of less than 3.75 nm FWHM (Fig. 2) while achieving a brightness of over 0.5 MW/cm~2-Sr at a 500-W power level.