Abstract

The generation of ultrashort optical pulses by compression techniques has received much attention recently with the chirp and dispersive delay line approach proving very successful.¹ In most cases, the chirp is obtained by a passive nonlinear interaction in a single-mode optical fiber (self-phase modulation). This approach has the disadvantage that the chirp rate depends on the peak optical power and thus Is applicable only to highpower pulses. In addition, power fluctuations (noise) are enhanced in this nonlinear process. An alternative approach to inducing a frequency sweep is to phase modulate the pulse electrooptically.^2,3 We designate this as active chirping, since power is supplied to the system. Following the phase modulator with a diffraction grating pair delay line results in a fairly compact pulse compressor with performance that is independent of optical power.

© 1988 Optical Society of America