Narrowing of the angular distribution of the radiation emitted by high-power injection lasers with a wide stripe contact by an external microselector

An investigation was made of the spatial and power characteristics of quantum-well heterolasers consisting of InGaAs/AlGaAs/GaAs heterostructures and emitting at 940 nm. An external microselector was used to obtain a nearly single-lobe angular distribution of the radiation from a laser with a stripe contact 50 μm wide. The maximum radiation power in the main lobe, characterised by the diffraction-limit divergence, was ~185 mW. At a fixed pump current the power delivered by the main lobe with the diffraction-limit divergence was 55% of the power of the same laser without the selector.