Supercontinuum Generation In A Photonic Crystal Fiber Pumped By Nanosecond Pulses

The main content of this paper is experimental obtaining supercontinuum source. As an important part of nonlinear fiber optics, the analysis research and theory technology of supercontinuum source are also constantly improved, which is paid attention to domestic and overseas researcher in the field of modern optical communication, biomedicine, spectroscopy, optical coherence tomography, optical metrology and so on. However, the photonic crystal fiber is a new kind of optical fiber with special structure, it has many advantages such as high nonlinearity and adjustable zero dispersion wavelength, so the supercontinuum can be obtained easily by its characteristics. A great deal of work about femtosecond and picosecond was done, so we mainly do the research in nanosecond.In this paper, we introduced the history of the supercontinuum and its recent results, the mechanics of supercontinuum generation is analysed. In experiments, the supercontinuum generated using the photonic crystal fiber and spliced fibers, which is opening the new way for the nanosecond pulses.The experimental results are shown by using photonic crystal fibers and spliced fibers:First, a 25-m-long photonic crystal fiber is pumped at the average peak power of 256 W and the repetition rate of 150 kHz, it puts out supercontinuum with 0.76 W power and the spectral range of over 1200 nm. According to the tunability of the repetition rate of this laser, the output supercontinua pumped at the same pump average power but different repetition rates of 50 kHz and 100 kHz were analysed. Finally, we found out that under the same pump average power, lower repetition rates of the pump which bring about wider spectral ranges of the supercontinua.In addition, the photonic crystal fiber and normal single-mode fiber was used to reduce loss in order to solve the problem of splice among photonic crystal fiber. Using a nanosecond pulsed laser as a pump source, through the method of the photonic crystal fiber and single-mode optical fiber of HI-1060 was spliced, the broadening process was analyzed:the 0.48 W supercontinuum with the spectral range of over 1100 nm was demonstrated in splicing of a 20-m-long photonic crystal fiber and 1-m-long single-mode optical fiber pumped at the average pump power of 2.2 W and the repetition rate of 150 kHz.