ABSTRACT
Ultrashort optical pulses are important and indispensable in many science and engineering application ˜elds. A lot of theoretical and experimental studies on the generation of ultrashort optical pulses have been explored and developed since the invention of the laser. Today, ultrashort optical pulses of several femtoseconds can be obtained by use of a commercially available mode-locked laser. However, there are some weaknesses in the mode-locked laser; it is dišcult to control the parameters of the optical pulses: the pulse width, the pulse shape, the pulse position in a time slot, the pulse repetition frequency, and the wavelength. It can also be diš cult to synchronize the pulse repetition frequency with other electrical signals although it is required in many applications. ™e available wavelength ranges of the optical pulses are restricted by the intrinsic characteristics of the gain medium used in the mode-locked laser. ™erefore, the development of a compact easy-to-use optical pulse source in arbitrary optical wavelength ranges still remains an issue.
