Future optical technologies are basically depending on and employing different types of optical waveguides. The fabrication of waveguides with different properties represents an expanding direction in both the industrial and scientific fields. In the current paper, we focus on studying the polymeric planar waveguides fabricated by the method of UV–excimer–laser lithography. We propose a general technique based on the WKB approximation and digital holographic interferometry to characterize slab waveguides with arbitrary refractive index profile. The necessary theoretical model is derived and the characterization method given in detail. Two samples are fabricated from polymethylmethacrylate (PMMA) polymeric material using different parameters for the used UV-laser. Then a phase-shifting digital holographic technique with the help of a Mach–Zehnder-like interferometer, is used to characterize the samples and measure their modified refractive index profiles. The resulting profiles are then fed to the proposed theoretical model and a full TE mode analysis is obtained. These results prove the ability of the proposed technique to analyze planar waveguides having any complicated refractive index profile.

中文翻译：

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基于WKB逼近和数字全息的表征平面波导的通用方法

未来的光学技术基本上取决于并采用不同类型的光波导。具有不同特性的波导的制造代表了在工业和科学领域中的扩展方向。在当前的论文中，我们专注于研究通过紫外-准分子-激光光刻方法制造的聚合物平面波导。我们提出了一种基于WKB逼近和数字全息干涉术的通用技术，以表征具有任意折射率分布的平板波导。推导了必要的理论模型并详细给出了表征方法。使用不同的紫外线激光器参数，由聚甲基丙烯酸甲酯（PMMA）聚合材料制成两个样品。然后，借助类似Mach–Zehnder干涉仪的相移数字全息技术来表征样品并测量其修正的折射率分布。然后将生成的轮廓输入到建议的理论模型中，并获得完整的TE模式分析。这些结果证明了所提出的技术分析具有任何复杂折射率分布的平面波导的能力。