Planar integrated optical processor based biomedical sensors

In an integrated planar optical system (IPOS) free space optical interconnections or processors are realized by folding the optical path in a glass substrate. In a typical IPOS for point-to-point optical interconnection, the light from a laser diode is directed by a diffractive optical element on the glass substrate and then reflected by a series of mirrors on the substrate to reach a photodetector or an optical fiber placed at the other end of the substrate. Thin metal film surface plasmon resonance (SPR) based noninvasive optical sensors are popular for measuring chemical species, refractive index or concentration of biochemicals in anatomical or biological samples. Since both IPOS and SPR based optical sensors use reflection of light it is possible to develop various types of "intelligent" optical sensors or measurement systems by placing SPR based optical sensors in IPOS. In such a sensor sensing and processing can be combined together. We discuss system design and performance analysis of such IPOS based SPR sensors.