Polarization-dependent dissipative soliton intensity modulation enabled repetition-rate-switchable CPA system

Abstract

We report a watt-level, repetition-rate-switchable all-fiber chirped pulse amplification (CPA) system by using polarization-dependent dissipative soliton intensity modulation effect. The intensity modulation for pulse repetition rate tuning is realized by combination of the polarization discrimination device (i.e., polarizer) and the polarization-rotating vector soliton (PRVS). Up to ~100% intensity modulation depth with a period of two cavity roundtrips for the PRVS seed was obtained by adjusting the dissipative soliton polarization state that was injected into the polarizer. Relying on this mechanism, the repetition rate of the output pulse from the CPA system can be dynamically switched between 1.37 MHz and 2.74 MHz. The pulse energy of ~2.0 μJ and ~2.2 μJ were achieved for the repetition rates of 1.37 MHz and 2.74 MHz, corresponding to 1.12 ps and 970 fs pulse duration, respectively. These findings would provide an alternative method for dynamic tuning of pulse repetition rate in high power laser systems, which also underpins the significance of fundamental research of vector dissipative solitons in practical applications such as flexible high-energy pulse laser systems.