Investigation of active pump-signal synchronization technique for a ps-pulse pumped OPCPA

Abstract

High-precision synchronization between pump and signal is one of the key issues that should be solved in picosecond short pulse pumped optical parametric chirped pulse amplification (ps-OPCPA). Based on the all-OPCPA laser facility in Research Center of Laser Fusion, China Academy of Engineering Physics, the high-precision active pump-signal synchronization technique used in its ps-OPCPA frontend is studied in detail in this paper. The synchronization is actively controlled by an amplified narrowband spectrum from the short ps-pulse pumped optical parametric amplification of a large chirped signal. By reasonably designing the time-domain broadening chirped coefficient of the signal in the feedback optical path, relative timing jitter between pump and signal of the ps-OPCPA frontend decreases from ps to one hundred fs, which greatly improves its energy and spectral stability. The root mean square (RMS) value of the relative timing jitter decreases from 458 to 93 fs, which improves the RMS instability of the output energy from 30.3% to 3.15%, and a stable wide spectrum with width greater than 100 nm is obtained in 7-min measurement.