Integrated Optical Sensor Platform based on Evanescent Field Coupling for Biochemical Sensor Applications

A photodetector integrated waveguide platform for diverse types of evanescent-wave sensor applications has been developed. Using this platform, surface plasmon resonance (SPR) detection has been demonstrated. The waveguide was made of SU-8 polymer as a guiding layer and siliconoxynitride (SiO_XN_y) as a cladding layer. The metal-semiconductor-metal (MSM) type photodetector coupled to the waveguide provides flexibility in design and fabrication compared to a pin (p-intrinsic-n) photodetector. We present a universal sensor architecture that can be used for evanescent-field based interrogation with (a) controllable refractive index and (b) integrated opto-electric signal conversion.