Tarnowski Karol, Martynkien Tadeusz, Mergo Paweł, Poturaj Krzysztof, Anuszkiewicz Alicja, Béjot Pierre, Billard Franck, Faucher Olivier, Kibler Bertrand, Urbanczyk Waclaw
Opt Express. 2017 Oct 30;25(22):27452-27463. doi: 10.1364/OE.25.027452.
We demonstrate a polarized all-normal dispersion supercontinuum generated in a birefringent silica microstructured fiber spanning beyond 2.5 µm. To our knowledge, this is the spectra reaching the furthest in mid-infrared ever generated in normal dispersion silica fibers. The generation process was studied experimentally and numerically with 70 fs pump pulses operating at different wavelengths on short propagation distances of 48 mm and 122 mm. The all-normal operation was limited by the zero-dispersion wavelength at 2.56 µm and spectral broadening was stopped by OH absorption peak at 2.72 µm. We identified the asymmetry between propagation in both polarization axes and showed that pumping along a slow fiber axis is beneficial for a higher degree of polarization. Numerical simulations of the generation process conducted by solving the generalized nonlinear Schrödinger equation (NLSE) and coupled NLSEs system showed good agreement with experimental spectra.
我们展示了在双折射二氧化硅微结构光纤中产生的跨越2.5 µm以上的偏振全正色散超连续谱。据我们所知，这是在正色散二氧化硅光纤中产生的中红外波段延伸最远的光谱。使用70 fs泵浦脉冲在48 mm和122 mm的短传播距离上以不同波长进行实验和数值研究了产生过程。全正色散操作受到2.56 µm处的零色散波长限制，并且光谱展宽在2.72 µm处的OH吸收峰处停止。我们确定了两个偏振轴上传播之间的不对称性，并表明沿慢光纤轴泵浦有利于获得更高的偏振度。通过求解广义非线性薛定谔方程（NLSE）和耦合NLSE系统对产生过程进行的数值模拟与实验光谱显示出良好的一致性。
