Study on Relative Timing Jitter between Ultrafast Er- and Yb-Fiber Laser Systems by Hybrid Active-Passive Synchronization

• Main Authors: Cai,Bo-Wei, 蔡伯偉
• Other Authors: Hsiang,Wei-Wei
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/99841410131907467043

碩士 === 輔仁大學 === 物理學系碩士班 === 101 === In this thesis, we investigate the relative timing jitter between 1 μm and 1.5 μm pulses from the ultrafast Yb- and Er-fiber laser systems under the hybrid active-passive synchronization. First of all, the 1 μm pulses generated from the Yb-fiber laser system are injected into the 1.5 μm mode-locked Er-doped fiber laser. The 1.5 μm pulses will change the center wavelength as well as the group velocity so as to achieve the passive synchronization with the 1 μm Yb-fiber laser system. On the other hand, the slow drift between 1 μm and 1.5 μm pulses resulted from the passive synchronization can be effectively removed by the electronic feedback servo which actively controls the cavity length of the Er-fiber laser via a piezo-transducer. In addition, we utilize the cross-correlation trace and the fluctuation of the sum-frequency-generation signal to measure the relative timing jitter. It is found that the relative timing jitter depends significantly on the relative position between the 1 μm and 1.5 μm pulses when they enter the co-propagating fiber section. This observed phenomenon can be explained theoretically by the pulse dynamics of frequency-modulated mode-locked fiber lasers. The minimum relative timing jitter obtained in our ultrafast Yb- and Er-fiber laser systems with such a hybrid synchronization is 0.8 fs (measurement bandwidth: 1.9 MHz).