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Study On Passively Mode-locking Erbium-doped Fiber Laser With Long Cavity

Posted on:2013-05-08Degree:MasterType:Thesis
Country:ChinaCandidate:J ChenFull Text:PDF
GTID:2268330392469946Subject:Photonics technology
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Ultra-short optical pulse with low repetition rate (tens of kHz) and high singlepulse energy can be widely used in micro-machining, surgery, biomedical sample andlaser radar testing. And it is one of the research hot topics at home and abroad.Passively mode-locking fiber laser with long (or ultra-long) cavity by simplyextending the length of cavity is just one of very effective lasers. This paper hastheoretically analyzed and experimentally studieded passively mode-lockingErbium-doped fiber laser with long cavity. Specific contents are as follows.1. Study on passively mode-locking Erbium-doped fiber laser with long cavity basedon nonlinear polarization rotation (NPR)(1) The relationships between mode-locking equation based on NPR and variousparameters in the cavity have been theoretically analyzed.(2) When the ratio of output coupling is80:20, stable and fundamental-ordermode-locking pulses with single pulse energy of45.17nJ have been experimentallyachieved at the repetition rate of50.92kHz.(3) While just changing the pump power or polarization controller, up to6thorderor11thorder passively harmonic mode-locking pulses have been observed,respectively.(4) When passively mode-locking fiber laser based on NPR and EDFA is operated,stable and fundamental-order mode-locking pulses with single pulse energy of27.97nJ have been experimentally achieved at the repetition rate of50.76kHz. And7thorder passively harmonic mode-locking pulses have been observed.2. Study on passively mode-locking Erbium-doped fiber laser with long cavity basedon NPR in SOA(1) The feasibility of passively mode-locking based on NPR in SOA has beentheoretically analyzed and numerically simulated.(2) When the injected current of SOA is112.7mA and the output power of EDFA is22mW, stable and fundamental-order mode-locking pulses with single pulse energy of33.12nJ have been achieved at the repetition rate of50.72kHz.(3) With the change of injected current of SOA and output power of EDFA, up to24thorder passively harmonic mode-locking pulses have been observed.3. Study on passively mode-locking Erbium-doped fiber laser with long cavity basedon nonlinear optical loop mirror (NOLM)(1) A new NOLM with a symmetrical coupler (50:50), a single mode fiber and apolarization controller in the loop has been theoretically analyzed.(2) Stable and fundamental-order mode-locking pulses with single pulse energy of 87.97nJ have been achieved at the repetition rate of48.88kHz.4. Study on passively mode-locking Erbium-doped fiber laser with long cavity basedon SESAM(1) Passively mode-locking Erbium-doped fiber laser with long cavity based onSESAM has been theoretically analyzed and numerically simulated.(2) When the pump power is112.3mW, stable and fundamental-order mode-lockingpulses with single pulse energy of2.95nJ have been achieved at the repetition rate of50.86kHz. And up to38thorder passively harmonic mode-locking pulses have beenobserved.
Keywords/Search Tags:fiber laser, passively mode-locking, low repetition rate, NPR, SOA, NOLM, SESAM
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