Ultra-wide-aperture diode lasers with high brightness through use of buried periodic current structuring

We report progress in the development of GaAs-based laser diodes with ultra-wide stripe widths of W = 1200 μm emitting at a wavelength of λ = 915 nm. In order to restrict ring oscillations and higher order modes in these ultra-wide devices we utilise periodic current structuring with a period of 29 μm and width of 20 μm. We compare the performance of a device with current structuring realised through contact layer implantation of the device after epitaxial growth, termed a 'Contact Implant' laser, and a device with buried current structuring close to the active region of the device realised using two step epitaxial regrowth and Buried-Regrown-Implant-Structure (BRIS) technology, termed a 'BRIS' laser. Quasi-Continuous Wave (QCW) measurement of the devices show that both the 'Contact Implant' and 'BRIS' laser achieve a very high peak output power of Popt = 200 W at a power conversion efficiency of ηE = 59% and ηE = 52%, respectively, with a peak efficiency of around 70%. QCW beam-quality measurements show that the 'BRIS' laser has a much reduced 95% power content far-field angle of 9°, compared to 12.7° for the 'contact implant' laser, at a power of P_opt = 100 W. Under Continuous Wave (CW) operation the 'contact implant' laser reaches an output power of P_opt = 68 W at ηE = 57% and the 'BRIS' laser reaches P_opt = 53 W at ηE = 50%, but with a reduced far-field angle of 11.9° at P_opt = 40 W for the 'BRIS' laser.