The drive laser system for CFEL

A reliable and compact drive system is one of the key components for the stable operation of FEL. We have developed a solid-state drive laser system to meet the requirements of the CFEL(CAEP FEL) research. The system consisted of a passive mode-locked oscillator with a timing stabilizer, a regenerative amplifier and a frequency conversion part. After the 4-th harmonics, the duration of 15 picoseconds Gaussian pulses with wavelength 266nm at a repetition rate 54.17MHz were obtained. These micropulses were contained within a macropulses envelope as long as 1 to 6μs, which was emitted from the drive laser at a repetition rate at 3Hz, 6Hz or 12Hz, one single micropulse energy as large as 4μJ was achieved. The design specifications, configuration and diode-pumped amplifier of the drive laser system are also described.