| Summary: | 博士 === 國立交通大學 === 光電工程系所 === 96 === The design and the impact of the fabrication errors for a flat-top planar waveguide concave grating demultiplexer have been investigated. A planar waveguide concave grating employing dielectric mirrors and a novel optical add-drop multiplexer (OADM) employing a planar waveguide concave grating have been proposed. For the design of a flat-top grating based planar waveguide demultiplexer, the three-focal-point and five-focal-point methods are introduced and analyzed with a design example. The structures and design procedures are discussed in detail. For the three-focal-point method, the highest -1-dB passband width of 27.19 GHz and the lowest ripple of 5.00 × 10 E-3 dB are achieved. For the five-focal-point method optimized with the multiobjective genetic algorithm, the highest -1-dB passband width of 30.53 GHz and the lowest ripple of 1.09 × 10 E-4 dB are achieved. The impact of fabrication errors, resulting in the random phase and amplitude errors, is also estimated. To yield a high-reflectance and low polarization-dependent loss (PDL), a planar waveguide concave grating employing dielectric mirrors is proposed. The PDL is below 0.05 dB when the proposed dielectric mirrors are used. A novel OADM employing a planar waveguide concave grating for the higher free spectral range (FSR) and smaller die size is proposed. The total die size is 70 × 61 mm^2 with the extinction ratios less than -59.20 dB.
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