Future high speed optical communication and computation systems will transmit, route, and manipulate extremely high rate streams of picosecond and femtosecond pulses. Recently researchers have been exploring techniques for generating optical pulse trains at repetition rates beyond those attainable by mode-locking or direct modulation. For example, Tai et al.1 employed the modulational instability in fibers to generate pulse trains at 100s of gigahertz repetition rates, and Sizer2 and Morimoto et a/.3 increased the rate of incident pulse trains by Fabry-Perot filtering. In the latter approach, the Fabry-Perot plays the rote of an amplitude filter, which eliminates many of the optical sidebands to increase the frequency spacing of those remaining. We describe conversion of individual femtosecond pulses into terahertz rate pulse trains by spectral phase filtering. Because we utilize phase-only filtering, the efficiency can be much higher than that possible by the amplitude filtering techniques.
© 1989 Optical Society of AmericaPDF Article