Silicon Carbide on Insulator Integrated Optics for Room/High-temperature Sensor Systems

We have been involved in developing a library of low-loss Si-on-insulator optoelectronic devices, and recently fabricated novel integrated optical phase modulators and beamsteering devices. We have also grown high-quality SiC-on-insulator (SiCOI) using SIMOX (a compliant substrate) and carboniza-tion, for electronic applications. The possibility of fabricating large waveguides, several microns in cross-section, makes SIMOX compatible with fiber-optics. Nevertheless, SIMOX suffers from the lack of a linear electro-optic (Pockels) effect in Si, thus, optical modulation is carried out by carrier injection or depletion, which limits the operation to a few tens MHz. .beta.-SiC exhibits a large electro-optic coefficient making it suitable for high-speed applications; it also could be easily integrated into SIMOX technology, and is very compatible with Si processing. 3C-SiC has a 2.3 eV bandgap and a refractive index of 2.6 in the red. Because the refractive index of sio2 is 1.47, optical waveguides can be constructed in SiCOI, where the sio2 buried layer isolates the SiC guide from the Si substrate. SiCOI photonics applications include optical, nonlinear optical, electro-optical, wave-length multiplexing, visible interferometers, visible signal routing (optical storage), and optical coupling to sensors. Phase I would optimize carbonization for optical applications (emphasis on the interface) and fabricate/test planar and rib waveguides. Phase II would design, fabricate, and evaluate planar and rib optical waveguides, optical modulators and visible interferometers in SiCOI substrates. The transparency of SiCOI at visible wavelengths allows high resolution for interferometric optical and sensing applications. The electro-optic effect of SiCOI offers optical modulation and phase compensation, all potentially at low cost. This combination is not offered by any other integrated optics technology.