Sanjabi Eznaveh Z, Eftekhar M A, Antonio Lopez J E, Kolesik M, Schülzgen A, Wise F W, Christodoulides D N, Amezcua Correa R
Opt Lett. 2017 Mar 1;42(5):1015-1018. doi: 10.1364/OL.42.001015.
We demonstrate that frequency generation in multimode parabolic-index fibers can be precisely engineered through appropriate fiber design. This is accomplished by exploiting the onset of a geometric parametric instability that arises from resonant spatiotemporal compression. By launching the output of an amplified Q-switched microchip laser delivering 400 ps pulses at 1064 nm, we observe a series of intense frequency sidebands that strongly depend on the fiber core size. The nonlinear frequency generation is analyzed in three fiber samples with 50 μm, 60 μm, and 80 μm core diameters. We further demonstrate that by cascading fibers of different core sizes, a desired frequency band can be generated from the frequency lines parametrically produced in each section. The observed frequency shifts are in good agreement with analytical predictions and numerical simulations. Our results suggest that core scaling and fiber concatenation can provide a viable avenue in designing optical sources with tailored output frequencies.
我们证明，通过适当的光纤设计，可以精确地调控多模抛物线折射率光纤中的频率产生。这是通过利用由共振时空压缩引起的几何参数不稳定性的起始来实现的。通过注入一个放大的调Q微芯片激光器的输出，该激光器在1064nm波长处输出400ps脉冲，我们观察到一系列强烈依赖于光纤纤芯尺寸的强频率边带。对三种纤芯直径分别为50μm、60μm和80μm的光纤样品中的非线性频率产生进行了分析。我们进一步证明，通过级联不同纤芯尺寸的光纤，可以从每个部分参数产生的频率线中产生所需的频带。观察到的频率偏移与解析预测和数值模拟结果吻合良好。我们的结果表明，纤芯缩放和光纤级联可为设计具有定制输出频率的光源提供一条可行的途径。
