Here we theoretically and experimentally demonstrated the arbitrary phase modulation of a general transmittance function (GTF) of the first-order optical comb filter based on a polarization-diversity loop structure, which employed two ordered waveplate sets (OWS’s) of a quarter-wave plate (QWP) and a half-wave plate (HWP). The proposed comb filter is composed of a polarization beam splitter (PBS), two equal-length polarization-maintaining fiber (PMF) segments, and two OWS’s of a QWP and an HWP with each set located before each PMF segment. The second PMF segment is butt-coupled to one port of the PBS so that its principal axis should be 22.5° away from the horizontal axis of the PBS. First, we explained a scheme to find four waveplate orientation angles (WOA’s) allowing the phase of an GTF to be arbitrarily modulated, using the way each component of the filter, such as a waveplate or PMF segment, affects its input or output polarization. Then, with the WOA finding method, we derived WOA sets of the four waveplates, which could give arbitrary phase retardations ϕ’s from 0° to 360° to a GTF chosen here arbitrarily. Finally, we showed phase-modulated GTF’s calculated at eight selected WOA sets allowing ϕ to be 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°, and then the predicted results were verified by experimentally measured results. It is concluded from the theoretical and experimental demonstrations that the GTF of our filter based on the OWS of a QWP and an HWP can be arbitrarily phase-modulated by properly controlling the WOA’s of the four waveplates.

中文翻译：

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具有四分之一和半波片有序集的一阶光学梳状滤波器的一般透射函数的任意相位调制

在这里，我们在理论上和实验上演示了基于偏振分集环结构的一阶光学梳状滤波器的一般透射率函数（GTF）的任意相位调制，该结构使用了四分之一波片的两个有序波片组（OWS） （QWP）和半波片（HWP）。提出的梳状滤波器由一个偏振分束器（PBS），两个等长的保偏光纤（PMF）段以及两个QWP和HWP的OWS组成，每组位于每个PMF段之前。第二个PMF段与PBS的一个端口对接，因此其主轴线应与PBS的水平轴相距22.5°。首先，我们解释了一种方案，该方案可以找到四个波片取向角（WOA），从而可以任意调制GTF的相位，使用滤波器的每个组件（例如波片或PMF段）影响其输入或输出偏振的方式。然后，利用WOA查找方法，推导了四个波片的WOA集，它们可以给出任意相位延迟φ的从0°到360°到这里任意地选择一个GTF。最后，我们显示了在八个选定的WOA集合处计算出的相位调制GTF，允许ϕ为0°，45°，90°，135°，180°，225°，270°和315°，然后验证了预测结果通过实验测量的结果。从理论和实验证明可以得出结论，通过适当地控制四个波片的WOA，可以基于QWP和HWP的OWS对我们滤波器的GTF进行任意相位调制。