Reaserch On The Fiber Laser Used For The Spatial Debris Detection

Comparing with semiconductor lasers, the fiber laser doped with rare-earh-element fiber as gain medium has a lot of advantages, such as good gain features, high coversion efficiency, low threshold power, high beam quality and compatibility with fiber communication systems. And comparing with traditional solid lasers, the fiber laser also can offer us a number of excellent characters, including small volume, light weight and so on. On the base of our laboratory environments, this paper focuses on the mode-locked Erbium-doped fiber laser and Yb³⁺-doped-double clad fiber laser containing sevral parts as below.Firstly, as consulting the Ido.Kelson's numerical model, we do research about the theory of double-clad fiber lasers and get some useful numerical simulations for the practice.And then, the physical mechanism of mode-locking in the fiber laser is investigated and the advantages of different mode-locking technologies have been analyzed. According to the process of mode-locked pulses propagating in the different cavities, we have summarized four models which discussed as below. From the time-domain mode-locked master equation, the physical mechanism of nonlinear polarization evolution mode-locking is analyzed in theory and the affects from cavity losses, dispersion, self-phase-modulation, and self-amplitude-modulation have been discussed particularly. In the experiment, we have presented an all-fiber mode-locked laser which contains the Er³⁺ -Doped Fiber Amplifier (EDFA), Polarization Beam Splitter (PBS), two all-fiber polarization controllers (PC), and so on. Under the experiment, we obtain stable mode-locked pulses with an average output power of 4.2μW, a repetition of 3.125MHZ at a central wavelength of 1564nm with 3dB bandwith of 0.46nm.At the end of this paper, fabricated by PBS, PC and some other equipment, an Erbium-doped fiber ring laser which emission central wavelength can be tuned from 1548.2nm to 1563.2nm continuously is experimentally demonstrated and analytically researched. And then, the tenability and dual-wavelength operation of the fiber lasers were analyzed with Jones Matrix. Under the numerical simulation, the theory is consistent well with the experiment.