High duty-cycle (>= 50%) operation of GaInAs/Al(Ga)AsSb quantum cascade lasers

Molecular beam epitaxy grown GaInAs/Al(Ga)AsSb heterostructures, offering conduction band offsets (gamma-valley) of >= 1 eV, appear to be the prime candidates for realizing high-performance quantum cascade (QC) lasers with short emission wavelengths. We focus on the development of processing technology to enhance the heat removal from the active region of the lasers by depositing a thick gold layer on both sides of the laser ridge. Due to the improved heat removal devices emitting at around 4.9 µm can be operated at high duty cycle (>= 50%) up to a heat-sink temperature of 130 K.