Biologically Inspired Evanescent Wave Sensor Using LinearArray Intra-Core Long Period Gratings

Nature has created inspiring detection mechanisms -- the mammalian olfactory system is an example. Our distinctive perception of smell ermerges not from selective receptors in the nose, but from an array of cross-reactive sensing elements and the brain's signal processing power. Biologically inspired, Physical Optics Corporation (POC) proposes an advanced evanescent wave sensor system for detecting volatile organic carbons. This system combines an array of fiber optic long period grating (LPGs) with neural network signal processing to identify and quantify individual analytes. LPGs, photolithographically inscribed in optical fiber, vastly enhance the interaction of core guided light with the cladding over conventional evanescent wave sensors. Thus, small analyte-induced changes in the cladding influences both the wavelength and intensity of the light in the fiber. POC's proposed cladding will attract and respond to analytes broadly yet differentially, with response times of a few seconds. During Phase I, POC will fabricate a working LPG-based sensor system and demonstrate its response to TCE and p-xylene in the presence of moisture. POC's sensor will be capable of reproducibly detecting analytes as liquid, DNAPL, thin-film, dissolved, and vapor forms, usable with cone penetrometers, reversible; field deployable; mass producible; low cost.