All-fiber, high power, rugged ultrashort-pulse laser source at 1550 nm

摘要

We present here the architecture of an all-fiber, high-power FCPA source emitting at 1550 nm. This system generates sub-300 fs pulses at a repetition rate of 22 MHz and with an average output power of 1.5 W after pulse compression. The power amplifier consists of a polarization-maintaining Er: Yb doped LMA fiber which results in a beam quality factor M~2 < 1.2. The seed laser pulses are stretched to 240 ps using dispersion-shifted fiber before being amplified and compressed using a bulk compressor based on a diffraction grating pair. The output power of the source is not limited by the onset of detrimental nonlinear effects such as self-phase modulation or stimulated Raman scattering since the accumulated nonlinear phase-shift in the power amplifier is well below n rad. Maximum output power is rather limited by the available pump power; a likely five-fold increase, given actual state-of-the-art technology, would thus yield a laser source that may serve as a substitute for widespread solid-state lasers in various fields such as laser machining, biophotonics and nonlinear optics.