Recovery dynamics in proton-bombarded semiconductor saturable absorber mirrors

Reduction of device response time, resulting from the proton bombardment of InGaAs/InP-based semiconductor saturable absorbers, was studied experimentally using an ultrafast degenerate, cross-polarized pump-probe technique. Proton bombardment is shown to reduce device response times to similar to1 ps at low optical excitation densities. Under high excitation, the device dynamics are dominated by induced absorption. The extended recovery of highly excited carriers appears to be less sensitive to defects created by bombardment. Mode locking was demonstrated with the proton-bombarded samples in an erbium-doped fiber laser. (C) 2001 American Institute of Physics.