Abstract

With low-timing jitter, passively mode-locked fiber lasers are very attractive seed sources for few-cycle-pulse OPCPA systems [1][2] where external synchronisation is always necessary. For precise synchronization of picosecond laser system, the timing jitter of each subsequent master oscillator pulse must be in the femtosecond timescale [3]. The simple, robust all-fiber design of soliton mode-locked laser is the top choice among other types of fiber laser. However, the pulse formation mechanism is complex and usually induces an additional frequency noise to the slow thermal variation of cavity length. Therefore, overall timing jitter is determined by the interplay between an amplified spontaneous emission (ASE), dispersion and nonlinearity of an optical cavity, soliton energy and spectral filtering [4]. Some nonlinearly induced frequency noise could be effectively suppressed within the locking bandwidth of the phase locked loop (PLL). Even so, the remaining part of noise outside the locking bandwidth contributes to the overall timing-jitter of fiber oscillator.

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