Tarnowski Karol, Martynkien Tadeusz, Mergo Paweł, Poturaj Krzysztof, Soboń Grzegorz, Urbańczyk Wacław
Opt Express. 2016 Dec 26;24(26):30523-30536. doi: 10.1364/OE.24.030523.
For the first time to our knowledge, we demonstrate a coherent supercontinuum in silica fibers reaching 2.2 µm in a long wavelength range. The process of supercontinuum generation was studied experimentally and numerically in two microstructured fibers with a germanium doped core, having flat all-normal chromatic dispersion optimized for pumping at 1.55 µm. The fibers were pumped with two pulse lasers operating at 1.56 µm with different pulse duration times equal respectively to 23 fs and 460 fs. The experimental results are in a good agreement with the simulations conducted by solving the generalized nonlinear Schrödinger equation with the split-step Fourier method. The simulations also confirmed high coherence of the generated spectra and revealed that their long wavelength edge (2.2 µm) is related to OH contamination. Therefore, improving the fibers purity will result in further up-shift of the long wavelength spectra limit.
据我们所知，我们首次在二氧化硅光纤中展示了在长波长范围内达到2.2 µm的相干超连续谱。在两根具有掺锗纤芯的微结构光纤中，通过实验和数值方法研究了超连续谱的产生过程，这两根光纤具有平坦的全正色散，针对1.55 µm泵浦进行了优化。光纤由两台工作在1.56 µm的脉冲激光器泵浦，其脉冲持续时间不同，分别为23 fs和460 fs。实验结果与采用分步傅里叶方法求解广义非线性薛定谔方程进行的模拟结果吻合良好。模拟还证实了所产生光谱的高相干性，并表明其长波长边缘（2.2 µm）与OH污染有关。因此，提高光纤纯度将导致长波长光谱极限进一步上移。
