High power GaAs∕AlGaAs lasers (λ∼850nm) with ultranarrow vertical beam divergence

The authors study 850nm GaAs∕AlGaAs longitudinal photonic band crystal lasers with a vertical far field divergence of 9° (full width at half maximum). Differential quantum efficiency of 95% is achieved at a cavity length of 500μm. A total optical output power from broad area multimode devices was up to 6.3W and a maximum continuous wave single mode power from narrow stripe devices was 270mW.