High-power broad-area 808 nm DFB lasers for pumping solid state lasers

Experimental investigations on high-power broad area (BA) distributed-feedback (DFB) lasers emitting in the wavelength range around 808 nm are presented. An output power of 4.7 W at 20 °C with a differential quantum efficiency of 1.06 W/A is achieved with BA-DFB lasers having a stripe width of 100 μm and a cavity length of 3000 μm. The measured lateral far field angle is about 10° at a power of 3 W. The vertical far field angle is near 29°. The emission has a narrow spectral width of 0.06 nm (FWHM) at 3 W and 0.10 nm at 4 W. From mappings of the optical spectra a wavelength variation with output power of Δλ/ΔP = 0.44 nm/W and with injection current of 0.4 pm/mA can be deduced. At a temperature of 50°C a maximum output power of 2 W is measured. From the measurements a temperature coefficient of Δλ/ΔT = 0.075 nm/K is determined.