Using nonlinear optical effects, we can control the optical spectra in various ways. Here, we discovered a novel phenomenon in ultrafast nonlinear fiber optics, namely, periodical spectral peaking. A narrow spectral dip on a pulse turns into a sharp, intense peak through a nonlinear effect. This phenomenon shows periodical evolution behavior in the soliton regime. If we use absorption spectra with constant frequency separation, like molecular gas absorption spectra, we can generate almost uniform frequency spanning sharp spectra with a linewidth on the order of a few picometers and sub-THz frequency separation. The generated spectral peak almost replicates the characteristics of the absorption spectra. Fundamental characteristics and physical mechanisms were investigated both numerically and experimentally. This phenomenon provides us with a novel approach to control the optical spectra and opens up new aspects and applications of nonlinear fiber optics.

中文翻译：

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光脉冲上的周期性光谱峰化

使用非线性光学效应，我们可以通过多种方式控制光谱。在这里，我们发现了超快非线性光纤中的一种新现象，即周期性频谱峰值。通过非线性效应，脉冲上的窄频谱骤降变成尖锐的，强烈的峰值。这种现象显示了孤子状态下的周期性演化行为。如果我们使用具有恒定频率间隔的吸收光谱（如分子气体吸收光谱），则可以生成几乎均匀的频率范围的尖锐光谱，其线宽约为几皮米和次太赫兹频率间隔。产生的光谱峰几乎复制了吸收光谱的特征。数值和实验研究了基本特性和物理机制。