Research On Pulse Temporal Compression And Spectral Broadening Based On Nonlinear Fiber

Since the1980s, the nonlinear fiber optics gradually generated and developedquickly. Due to the wide range of applications of nonlinear fiber optics, more andmore people devoted themselves into this research field. Supercontinuum generationand pulse compression based on nonlinear effects of fiber are two importantapplications of nonlinear fiber optics. This thesis studied the nonlinear effect ofoptical fiber in theory and experiment. A compact all-fiber supercontinuum source issuccessfully developed. Pulse compression based on all-normal dispersion fiber isdemonstrated. The main works are summarized as follows:1. In the aspect of pulse compression based on nonlinearity of fiber, pulsecompression based on all-normal dispersion is experimentally studied. The fiber usedin the experiment has an all-normal dispersion profile in800nm-1600nm. In suchfiber, soliton generation and fission are suppressed. Highly coherent spectra aregenerated, which preserve a single pulse in the time domain. In the experiment,changing the length of the all-normal dispersion fiber, the average power, pulse widthand chirp of the input pulse to control the nonlinearity and applying prism pair enablethe generation of22fs pulses.2. In the aspect of supercontinuum generation, a compact all-fibersupercontinuum source is successfully developed. The seed laser in the experiment isa dissipative all-fiber mode-locked laser working in all-normal dispersion region. Thenonlinear polarization rotation mode-locking technology is applied. The output pulsewidth of the dissipative soliton is5.18ps with a repetition rate of24MHz. The seedlaser pulse is amplified with15m double-clad ytterbium-doped fiber, then is coupledinto a10m-long photonic crystal fiber. The supercontinuum generation achieves morethan one octave of bandwidth(550nm-1750nm) at700mW average power. Theamplification process of dissipative soliton and the mechanism of supercontinuumgeneration in anomalous dispersion region of photonic crystal fiber are systematicallystudied.