Method of Ultrashort Optical Pulse Measurement

This paper describes the principle of ultra-short optical pulse measurement including novel measuremet methods that have recently been developed. The SHG auto-correlation method is most widely used to estimate the short optical pulse width. However, two-photon absorption in LED's and photodiodes has been applied to generate the nonlinear correlation signal instead of SHG, and has revealed remarkable performance in the short pulse measurement. On the other hand, the cross-correlation method such as the optical sampling method has been introduced into the measurement of transient response of optical devices and the pulse pattern measurement in ultra-high speed optical transmission systems. The reconstruction of the waveform and phase from the measured correlation signal is also an important problem. This paper deals with the FROG (Frequency Resolved Optical Gating) developed for this purpose.