Fast-Recovery of the Amplitude and Phase of Short Optical Pulses Using a Frequency-Swept Source Based Heterodyne Measurement

We propose a very fast heterodyne technique to recover the amplitude and phase of short optical pulses generated, e.g., by a mode-locked laser. A linearly swept frequency source is used to scan the entire optical spectrum of the mode-locked laser in a single continuous sweep. The beat signal is recorded on a fast oscilloscope and then digitally processed allowing the simultaneous recovery of the amplitude and the phase. This measurement is fast (less than 2μs and requires no prior spectral information about the signal under test.