Low-loss silicon carbide optical waveguides for silicon-based optoelectronic devices

A SiC-on-SiO/sub 2/ waveguide structure is proposed and analyzed. The analysis shows that the planar SiC waveguide has low loss and good beam confinement in the guiding core for the fundamental mode at 1.3 mu m and 0.7 mu m. In addition, such a waveguide displays strong mode discrimination (>20 dB) between the fundamental and the higher-order modes. Single-mode SiC/SiO/sub 2/ rib waveguides with large dimensions are also analyzed. The waveguides are single-moded even if the waveguide dimensions are large as long as the rib width-height ratio is appropriate. In addition, such large-dimension rib waveguides should exhibit low loss due to the large SiC-layer thickness and can be used for waveguiding either over the communication wavelength range 1.3-1.6 mu m or the silicon light source at 0.7 mu m. Furthermore, electrooptic modulators can potentially be fabricated with SiC-on-SiO/sub 2/ waveguide structures compactly. Such modulators should offer potential candidates for high-speed electrooptic modulation for silicon-based optoelectronic devices.<
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