| Summary: | 碩士 === 國立宜蘭大學 === 電子工程學系碩士班 === 102 === In this master thesis, we use the photonic crystal (PC) to realize a polarization beam splitter which used a ring structure in the coupling region.
Photonic crystals have the feature that we call photonic band-gap. PC can become a good waveguide if the feature has a combination with defect in photonic crystal. PC also can be used for designing integrated optical devices which will achieve high efficiency and low loss in transmission. In two-dimensional PC, the input light has two sorts of polarizations. The oscillation directions of these two polarizations are perpendicular to each another. One of oscillation directions is perpendicular to the cylinder structure of photonic crystal, and the other one is parallel to it. That means if we use annular structure to replace the cylinder structure, one of polarizations will have more effect than the other one. So we use this feature to research the annular PC which has the wider photonic band gaps than cylinder PC.
We have purposed a coupling type polarization beam splitter (PBS) with two line defects structure. In the coupling region of this structure, we introduce the annular structure in our previous work. With the features of the annular structure, our PBS can separate two polarizations and it does not need multiple coupling. Furthermore, the PBS has great transmission efficiency and smaller size.
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