A new method to measure the chirp of pulses emitted from repetitively
driven lasers is described, The technique relies on spectrally filteri
ng the output of the laser, detecting it, and then measuring its phase
with respect to a reference signal via a mixing technique. We demonst
rate the method by measuring the chirp of pulses emitted from monolith
ic CPM lasers, The measured chirp agrees with that predicted by a newl
y developed model of the CPM lasers.