Numerical Study of Few-Cycle Pulses by Nonlinear Compression in Two-Photon Semiconductor Amplifiers

Optical pulse compression down to a few optical cycles by the ultrabroadband gain of nonlinear two-photon process in semiconductors is proposed. Recent experimental demonstration of semiconductor two-photon gain (TPG) has motivated this analysis of ultrashort pulse dynamics with realistic semiconductor parameters. Comprehensive material model, including TPG, carrier depletion, linear absorption, Kerr effect, plasma response of injected carriers, and the material dispersion were numerically simulated using the finite-difference time-domain method. Pulse compression down to a few optical cycles is theoretically predicted.