Experimental And Theoretical Investigations Of Bound-state Pulses In Nanotube-mode-locked Fiber Laser

The investigations of bound-state pulse not only enrich the output state of fiber laser, but also have the potential applicants in the fields of lasers, optical communications and high-resolution optics. Therefore,this is a very significant research topic. In this paper,I study the bound-state pulses in nanotube-mode-locked fiber laser with different dispersion regime. I have obtained the bound-state conventional solitons(CS) and stretched pulses. The major researches of this paper can be described as follows:1. The single-wall carbon nanotube(SWNT) films are prepared in the experiments. The corresponding optical characteristics can be studied by using of femtosecond pulse, The SWNT saturable absorber can modeled by a simple two-level model: saturation intensity I sat = 30 m W/cm2, nonsaturable absorption a ns = 80% and linear limit of saturable absorption a0 = 10.92%. The data certify that the SWNT films can be served as mode locker in fiber laser.2. In the anomalous dispersion regime, two chirped fiber Bragg gratings are exploited as mirrors in the linear cavity, the bound-state CS are observed in nanotube-mode-locked fiber laser. The experiment show that the pulses duration and separation are 6.3 ps and 23 ps,respectively. Numerical simulations con fi rm the experimental observations and are in good agreement with the experimental results. Both experimental results and numerical predictions reveal that the formation of bound-state CSs is a result of direct pulse-pulse interaction, and show that the bound-state CSs are strongly stable.3. In the near zero dispersion regime, I have theoretically and experimentally investigated a stretched-pulse fi ber laser mode-locked by a SWNT saturable absorber. Single pulse and bound-state pulses are obtained respectively by adjusting the pump power and polarization controller.The numerical simulations are in good agreement with the experimental observations. The formation of bound-state stretched pulses is also a result of direct pulse-pulse interactions.