ABSTRACT
This chapter proposes differential photosensor which is introduced by way of its design, theory, and applications to optical wireless communication (OWC) and optical wireless location (OWL) technologies. Sensor technologies gather information from distributed targets by way of two general formats: passive sensing and active sensing. The cubic nature of the photosensor architecture lends itself to arrayed detector distributions with interleaved photosensors distributed across surfaces. Such periodic arrays can be scaled up to increase the overall signal amplitude without sacrificing the individual photodiode (PD) response times. The geometrical nature of the differential photosensor allows it to act as a retroreflector, by reflecting a fraction of the incident light back to its source, and a photodetector, by sampling the incident light with the PDs. Differential combinations of PD photocurrents can be used to triangulate the direction of the optical source and align the structure along the optimal orientation. The chapter presents the theory for the resulting retroreflection and photodetection characteristics.
