| Summary: | 碩士 === 國立交通大學 === 電子工程系所 === 95 === In this study, the multimode interference (MMI) effect and its principle (self-imaging) in 2-D photonic crystal waveguides (PCWs) are investigated. By using the finite-difference time-domain (FDTD) computation performed on a multimode photonic crystal line-defect waveguide, the self-imaging phenomenon and the imaging positions along the propagation axis are observed, and it is found that the results are in good agreement with those derived from the modal propagation analysis (MPA). This mean that the analytic methods for MMI in conventional multimode waveguides still can be applied in 2-D line-defect PCWs. We take several multimode PCWs for examples to confirm this idea. Moreover, we design a photonic crystal 1-to-2 1.480/1.625μm wavelength-division-demultiplexer based on MMI in PCWs. Its performance in numerically simulated by FDTD computation. The results show that the insertion loss is about 0.33 (dB) for the wavelength 1.480μm, and 0.33 (dB) for 1.625μm. The contrast is about 15.45 (dB) for the wavelength 1.480μm, and 12.9 (dB) for 1.625μm, respectively.
|
|---|
