METHOD AND APPARATUS FOR DISTRIBUTED SENSING OF VOLATILES AND A LONG PERIOD FIBER GRATING SENSOR WITH MODULATED PLASTIC COATING FOR ENVIRONMENTAL MONITORING

摘要

Optical time domain reflectometry caused by absorption of a volatile or analyte into the fiber optic cladding is used an optical nose. The fiber optics (14) are covered with a gas permeable film (44) which is patterned to leave millimeter wide gas permeable notches (48a-48d). The notches contain a sensing polymer that responds to different gases by expanding or contracting.