Synchronization Maintenance of Synchronized Time-Lens Source in the Presence of Repetition Rate Drift of the Mode-Locked Laser for Coherent Raman Scattering Microscopy

Synchronized time-lens source can be synchronized to mode-locked lasers and has emerged as a new solution for two-color synchronized laser source. It has found widespread applications in coherent Raman scattering microscopy. Relative timing jitter between the synchronized time-lens source and the mode-locked laser is the key parameter for estimating the synchronization performance. Recently, it has been demonstrated theoretically that if the repetition rate of the mode-locked laser fluctuates around a mean value, then the relative timing jitter is only a fraction of the intrinsic timing jitter of the mode-locked laser. However, in some practical mode-locked laser systems, the repetition rate may also suffer from directional drift. Whether the time-lens source can be synchronized to such mode-locked lasers remains unknown. Here, we establish a physical model to account for both the directional repetition rate drift and the stochastic repetition rate fluctuation of the mode-locked laser, and demonstrate detailed numerical simulation results of the relative timing jitter in such synchronized systems. Our results indicate that various forms of repetition rate drift lead to an increase in the relative timing jitter compared with the drift-free case. However, the relative timing jitter is still smaller than the stochastic repetition rate fluctuation of the mode-locked laser when there is no drift, under practical experimental conditions. This suggests that the synchronized time-lens source is still a robust solution for two-color synchronized laser source.