Timing Jitter Of Mode-Locked Fiber Laser

Recent years, the output pulse energy of mode-locked fiber laser has been greatly improved by introducing varieties of pulse formation mechanism. At the same time, the pulse width has been compressed as well. Most importantly, the performance of mode-locked fiber lasers is equivalent to the bulk lasers. Compare with the bulk lasers, mode-locked fiber lasers have many advantages which have attracted extensive attentions of researchers, such as cheap, compact, easy to fabrieate and insensitive to the environment. As the mode-locked fiber lasers are widely used in optical sampling, analog to digital conversion and optical frequency comb etc., among which require ultra-low timing jitter and ultra-low phase noise, researches on the timing jitter and phase noise of the fiber lasers have become the key issues. This dissertation mainly focuses on the performance parameters of mode-locked fiber lasers, especially on the timing jitter and phase. noise. Via theoretical derivation and analysis, some measurements are carried out to reduce timing jitter and phase noise. Finally, we propose a practical application of fiber laser used to monitor the optical signal leak out from macro bending fiber, and show some simulation results.Based on the current experiment conditions, the main research efforts are summarized as follow:1.The pulse shaping process in a passively mode-locked fiber laser has been investigated theoretically. And an all normal dispersion cavity active harmonic mode-locked fiber laser with full-polarization devices in the laser cavity has been built experimentally. The influences of the pump power on the dissipation solitons has been studied. The maximum output power of35.6mW was obtained for the single pulse operation which corresponded to the pulse energy of1.26nJ at the fundamental repetition rate of33.3.46MHz. The pulse SNR is76dB and the FWHM of the pulse is30.1ps.At last we achieve precise control of the wavelength at1029.35nm to1079.25nm.2.According to soliton perturbation theory,we have solved the power spectral density of the timing jitter, phase noise, intensity noise and frequency jitter noise of the mode-locked fiber laser in theoretical expression. A simple soliton pulse time jitter noise spectrum was achieved.. Based on the theoretical analysis, further researches on effects of the cavity length, gain, gain.spectral width and other parameters on noise have been carried out and, some basic results were concluded:narrow gain bandwidth, high, repetition frequency, slightly dispersion and proper gain could greatly reduce time jitter induced by the quantum noise. At last related initiatives to reduce time jitter a’re pointed out as well.3. In the application of fiber lasers, we analyze and simulate the coupling efficiency of side polished fiber coupling, Some simulation results of coupling efficiency has been shown.The40%coupling efficiency could be achieved when the radius of bending fiber is14mm and the distance of two fibers is5um.