Mode-locked All-fiber Dumbbell-shaped Laser Based On Nonlinear Optical Loop Mirror

Mode-locked all-fiber dumbbell-shaped laser is a novel passively mode-locked fiber laser based on nonlinear optical loop mirror(NOLM).In this dissertation,mode-locked all-fiber dumbbell-shaped laser are investigated.After describing the mode-locking principle and designing the laser configuration,we accomplished the primary experimental research work of mode-locked all-fiber dumbbell-shaped laser.The major results in this dissertation are as follows:1.By simultaneously using one NOLM and one nonlinear amplifying optical fiberloop mirror(NALM)as mode locking components,noise-like pulse with output power of 200 mW,single pulse energy close to 20 nJ,spectrum centered around 1050 nm with 3dB bandwidth of about 10 nm,and repetition rate of 8.85 MHz is obtained from a mode-locked all-fiber dumbbell-shaped laser with double pump sources.2.By inserting a band-pass filter into the laser cavity of mode-locked all-fiber dumbbell-shaped laser with double pump sources,dissipative soliton resonance pulse mode-locking is achieved.The laser output power is 300 mW with single pulse energy over 40 nJ.The laser spectrum is centered around 1064 nm with 3dB bandwidth of 1.2 nm.The repetition rate is 7.19 MHz.3.A novel mixed mode-locking fiber laser based on one NALM and one semiconductor saturable absorber mirror(SESAM)is investigated,achieving output power of 10.9 mW with repetition rate of 9.32 MHz.The experiment research results give us a better understanding to the mode-locking principle and the characteristics of mode-locked all-fiber dumbbell-shaped laser.With relatively high output power and pulse energy,this laser can be used in the high power fiber laser as a seed source that can reduce the difficulty of the followed power amplification.