Application of Pulse Compression and Shaping to the FEL (Free Electron Laser) Photoelectric Injector

摘要

We discuss the application of self-phase modulation and grating pulse compression to the generation of temporally trapezoidal optical pulses for controlling the electron beam emitance and energy spread in an FEL photoelectric injector. Pulse compression i n a single-stage pulse compressor, with background reduction based on the nonlinear birefringence of the optical fiber, yields 3-ps, compressed pulses without background pedestals or sidelopes. Trapezoidal, flat-topped pulses with 20-ps FWHM and 4-ps risetime have been obtained through self-phase modulation and group-velocity dispersion of the 3-ps pulses in a second fiber. Pulse shaping through Fourier transform amplitude and phase masking in the frequency domain and the amplification of the trapezoidal pulses ar also discussed. 14 refs., 9 figs. (ERA citation 13:030866)