Carrier capture times in 1.5 μm multiple quantum well optical amplifiers

The carrier capture times in multiple quantum well semiconductor amplifiers of different structures are studied under high plasma density conditions. Fast (<1 ps), slow (≳150 ps), and intermediate time constants (2–7 ps) are identified in InGaAs quantum well structures. The intermediate time constant is attributed to carrier diffusion in the cladding layers and identified as the carrier capture time. Short capture times can be achieved by proper design of the device structure.