Thermo-optic Properties in PECVD Silicon Rich Silicon Carbide

Abstract

We study the thermo-optic coefficient of silicon carbide with different silicon content. We demonstrate a clear trend between the silicon content and the thermo-optic coefficient which measured as high as 1.88× 10−4 ℃−1.

Noise Tolerant Photonic Bowtie Grating Environmental Sensor

“…Some sensor architectures such as photonic crystal fiber grating refractive index sensors achieve very high refractive index sensitivity, in the 1 × 10 –6 range, and mechanical tolerance, but they are not temperature compensated and require the analyte to be infiltrated into the fiber as well as a high performance spectrometer for the readout, which limits these sensors to laboratory research. The susceptibility of photonic sensors to thermal fluctuations is also well-known, − especially in silicon-based sensors due to silicon’s high thermo-optic effect of d n /d T = 1.8 × 10 –4 1/K. − A common solution to the temperature dependence of silicon photonics is to use a polymer coating that exhibits the opposite thermo-optic effect, thereby making the device largely temperature insensitive. , Such polymers, however, are usually not compatible with some of the harsher biological or industrial environments where the sensor needs to operate; moreover, the coating may compromise the operation of the sensor by screening the evanescent tail of the mode. Other researchers have incorporated structure compensation, , measured fringe contrast , and implemented dual micro resonators , in Fabry–Perot fiber sensors to compensate for temperature variations, achieving limits of detection in the range of 10 –5 to 10 –3 refractive index units.…”