Analysis of ultrashort pulse-shape measurement using linear interferometers

A general interferometer composed of linear filters (both time stationary and frequency stationary) and a square-law detector is analyzed, and the possibilities for measuring the spectral phase of ultrashort optical pulses are enumerated. It is found that with purely time-stationary filters the phase spectrum cannot be determined with an integrating detector but that a detector with a finite bandwidth permits such a determination. It is also shown that the phase may be measured with a time-nonstationary filter and an integrating detector. The possibilities for realizing the system are evaluated.