Pulse temporal and spatial chirping by a bulk Kerr medium in a regenerative amplifier

The temporal and spatial chirping of a pulse by a bulk Kerr medium in a regenerative amplifier is analyzed. Utilizing the waveguide nature of an optical resonator, temporal self-phase modulation can cumulate through multiple passes as large as /spl sim/40 rad, while the nonlinear phase shift associated with spatial chirping is confined to /spl sim/1.5 rad, thus reducing the degree of spatial chirping to less than 4 percent. We show that the Guoy phase shift reduces the magnitude of self-phase modulation. Experimental results of pulse chirping in a neodymium:phosphate glass regenerative amplifier agree with the theoretical calculations. Direct compression of highly chirped, amplified pulses by a pair of gratings produces 10 /spl mu/J, 300 fs pulses at a 500 Hz repetition rate.<
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