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Research On Passively Harmonic Mode-locking Fiber Laser

Posted on:2017-08-18Degree:MasterType:Thesis
Country:ChinaCandidate:M LiFull Text:PDF
GTID:2348330518496099Subject:Electronic Science and Technology
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Passively mode-locked ytterbium(Yb)-doped fiber laser have attracted great interests owing to their wide applications in the fields of dense wavelength division multiplexing(DWDM)optical communication,optical sensing,biomedical,military,industry and so on.Ultra-short pulse has always been the frontier hot research topic in the field of fiber laser.In this thesis,by studying the theory,demonstrating experiments of the passively mode-locked Yb-doped fiber laser,and analyzing its mechanism and performance,we designed and experimentally demonstrated three passively mode-locked fiber lasers,we received dissipative solitons with tunable wavelength,multi-wavelength,and/or harmonic mode-locking.The main research content and results are as follows:1.We established an all-fiber ytterbium-doped mode-locked fiber laser based on nonlinear polarization rotation(NPR)and observed the dissipative soliton(DS).Spectrum of mode-locked DS can be tuned from 12.0nm to 16.0nm with increasing of the pump power.Its wavelength can be tuned from 1055.1nm 1035.3nm(tunable range is about 19.8nm)by adjusting the states of polarization.In addition,by optimizing the resonator,dual-and triple-wavelength dissipative solitons were obtained.2.We experimentally demonstrated a tunable multi-wavelength DSs Yb-doped fiber laser based on semiconductor saturable absorption mirror(SESAM)and tunable Lyot-Sagnac filter.Due to the tunablity of the filter,more than triple-wavelength DSs were generated in the fiber laser.From single-to six-wavelength DSs mode locking was/were generated by adjusting the filter and the pump power.To the best of our knowledge,the six-wavelength output has the most wavelengths in multi-wavelength DSs fiber lasers that have been reported so far.When the DS mode-locked fiber laser was working on single-wavelength operation,its wavelength can be tuned from 1068.8nm to 1075.9 nm by adjusting the tunable filter.3.Based on the photonic crystal fiber(PCF)and SESAM,we experimentally demonstrated a passively harmonic mode-locking fiber laser.By reducing the the loss of fusion between the PCF and single-mode fiber(srSMF),up to 12th of harmonic mode-locking pulse was observed,corresponding to the repetition frequency of 61.6 MHz.4.A novel passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all normal dispersion based on SESAM and a tunable Lyot-Sagnac filter was experimentally demonstrated.By only tuning the bandwidth of the filter at fixed pump power,the repetition rate of 9.87 to 167.8MHz(corresponding to 17th-order harmonic)was obtained,which is the highest repetition rate and highest harmonic order for passively harmonic mode-locked dissipative soliton Yb-doped fiber laser with all normal dispersion,to the best of our knowledge.The signal-to-noise ratio and super-mode suppression ratio for all harmonic orders are higher than 65dB and 35dB respectively,which means the high stability of the fiber laser.
Keywords/Search Tags:dissipative soliton, passively mode locking, wavelengthtunable, multi-wavelength, harmonic mode locking fiber laser
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