High power fiber laser system for a high repetition rate laserwire

We present the development of a high power fiber laser system to investigate its suitability for use in a transverse electron beam profile monitor, i.e., a laserwire. A system capable of producing individual pulses up to 165.8 +- 0.4 μJ at 1036 nm with a full width at half maximum of 1.92 +- 0.12 ps at 6.49 MHz is demonstrated using a master oscillator power amplifier design with a final amplification stage in a rod-type photonic crystal fiber. The pulses are produced in trains of 1 ms in a novel burst mode amplification scheme to match the bunch pattern of the charged particles in an accelerator. This method allows pulse energies up to an order of magnitude greater than the steady-state value of 17.0 +- 0.6 μJ to be achieved at the beginning of the burst with a demonstrated peak power of 25.8 +- 1.7 MW after compression. The system is also shown to demonstrate excellent spatial quality with an M2 of 1.26 +- 0.01 in both dimensions, which would allow nearly diffraction limited focusing to be achieved.