9523456 Sirkis This proposal describes the development of a sensor system capable of remotely monitoring the progression of decay in wood utility poles used to support overhead transmission lines in power distribution networks. This shall be done by detecting one or more of the following chemical/biological metrics of decay: (1) presence and/or concentration of decay causing fungi, (2) end-products of metabolic growth of the decay causing fungi, (3) decrease in critical nutrients required to support fungi metabolic growth, (4) increase in enzymes, (5) decrease in the ratio of carbon to nitrogen, and/or (6) decrease in pH. Detection of these chemical metrics of decay shall be accomplished by developing a multifunctional integrated optic-based sensor system that utilizes Bragg gratings etched into planar waveguides. Part of the waveguide will utilize Bragg grating with an upper cladding fabricated from chemical species. As binding occurs, the propagation constant of the waveguide changes, resulting in corresponding changes in the Bragg wavelength. Highly sensitive interferometric-based demodulation schemes will be developed to monitor the chemically-induced changes in the Bragg wavelength. A higher order Bragg grating located on the same waveguide will be used aid optically probe the cellular structure in order to monitor pH and/or florescence indicative of the targeted metabolic by-products of decay. The sensor technology we propose offers (1) high rejection of electromagnetic noise, (2) compatibility with optical fiber telemetry so that sensor data can be transmitted simultaneously with communications signals thereby making possible remote pole inspection, (3) multiplexibility so that many sensors can be fabricated into the same planar waveguide, and many planar waveguides can be located along the same optical fiber lead, and (4) manufacturing processes similar to those used in the microelectrics industry thereby making possible sensors amenable to l ow cost mass production. ***
