Modeling transient gain dynamics in a cladding-pumped Yb-doped fiber amplifier pulsed at low repetition rates

Summary form only given. For deep space optical communication links, high peak-power laser sources with repetition rates less than 100 kHz are required. A potential candidate is the high power, cladding-pumped, Yb-doped fiber amplifier (YDFA) with a pulse-position-modulated seed oscillator. A device developed under contract by IPG Photonics met the requirements of almost 10 kW peak power with pulsewidths less than 30 ns at 3.5 kHz. However, at higher repetition rates (20 to 50 kHz), nearly flat pulses with peak power less than 1 kW were obtained. To understand and optimize this behavior, we have simulated the performance of a pulsed YDFA.