  Short pulse lasers are used to characterize the nonlinear response of
amplified photodetectors. Two widely used balanced detectors are characterized
in terms of amplitude, area, broadening, and balancing the mismatch of their
impulse response. The dynamic impact of pulses on the detector is also
discussed. It is demonstrated that using photodetectors with short pulses
triggers nonlinearities even when the source average power is well below the
detector continuous power saturation threshold.
