Waterproof fiber optic chemical sensors

Abstract From the Canadian patent

A fiber optic chemical sensor (10) is made water repellent by attaching a plurality of long, hydrophobic chains e.g. silane, polymers, to the surface. The chains extend from the surface and form a semi-permeable barrier which repels water molecules while selectively passing analyte molecules therethrough. In one configuration, the hydrophobic chains are attached substantially uniformly over the clad (14). In a second configuration clad (26) is a, plurality of spaced stripes with the hydrophobic chains attached in the gaps (30) between the stripes. In another configuration a, patterned hydrophobic coating (50) of alternating thick and thin segments (44, 46) is formed on the clad (43).