InGaAs/GaAs frequency tunable twin guide quantum well laser designed for steerable surface emission

Based on a frequency tunable twin-guide (TTG) InGaAs/GaAs multiple quantum well (MQW) laser structure, we developed a novel design concept for a surface emitting laser device enabling spatial beam steering. Utilizing a change in the refractive index of the parallel monolithically integrated modulator diode due to carrier injection, we observe a continuous emission frequency (wavelength) shift up to Δf = 85 GHz (Δλ = - 0.35 nra). For this preliminary structure the experimental results are consistent with our model calculations. Based on the theoretical model, for an optimized device a tuning range of Δf = 1600GHz (|Δλ ≥ 5 nm) is expected. For the novel surface emitting device design, we make use of an additional structure on top of the TTG laser including a second waveguide and a grating. This will enable a wavelength dependent surface emission angle, i. e. continuous beam steering, by coupling the laser and the surface mode. A calculational model was developed to estimate the steering characteristics in dependence on the dielectric device structure including mode guiding and the surface grating shape.