| Summary: | 碩士 === 國立中山大學 === 光電工程研究所 === 91 === In this thesis, S-bend waveguides and ring resonant filters with multimode interference (MMI) couplers have been designed and fabricated.
The single-ring filters are designed to have free spectral ranges ( FSR''s) of 33.3GHz, 40GHz and 50GHz. The FSR''s of double-ring filters are 100GHz and 200GHz. The splitting ratios of the 9-�慆 wide MMI couplers are 50：50 and 0：100. Those of 8-μm wide MMI''s are 15：85 and 50：50. In the S-bend waveguide section, test structures with four different curve radii and angles are included.
In the fabrication process, the sides of the waveguides are firstly dry- etched to a depth of about 1.6μm. This is followed by a selective wet chemical etch to stop at the top of the i-region. Finally, we use polyimide to planarize the sides of the waveguide and evaporate Cr-Au electrode over the polyimide.
In device measurements, the preliminary measurement of the S-bend waveguide losses has been completed. The loss in waveguides with offset at the curved junctions is found to be lower than in those without offset. The best condition is 0.731dB/900 at R=100�慆.
|
|---|
