Temperature Self-Compensated Optical Waveguide Biosensor Based on Cascade of Ring Resonator and Arrayed Waveguide Grating Spectrometer

A temperature self-compensated optical waveguide biosensor employing the cascade of a ring resonator and an arrayed waveguide grating (AWG) spectrometer based on silicon-on-insulator platform is proposed and theoretically investigated. By means of appropriately choosing the waveguide widths for ring waveguide and array waveguide, respectively, the AWG spectrometer is designed to have the same temperature dependence as the ring sensor in aqueous solution, pertinent to most biosensing applications, with temperature change to eliminate the temperature-induced sensor signal change in detection result. A center of gravity detection technique is used for processing the power distributions at all output channels of the AWG spectrometer to derive the resonance wavelength of the ring sensor. The simulated results show that the resonance wavelength shifts derived from the AWG spectrometer for the ring sensor/sensor arrays are only dependent on the refractive index change of the aqueous solution and remain unchanged regardless of the environmental temperature variation. Compared with the conventional measurement for the ring sensor, this proposed optical waveguide biosensor without the needs for an external high-resolution light source/spectrometer and extra processing for the detected data to eliminate the temperature influence can find an application in smartphones/potable sensor detection systems for on-site testing.