Organic vapors detection using single mode fiber at third telecommunication window

An optical fiber sensor to detect volatile organic compounds (VOCs) is presented in this work. A material that shows a color change (from orange to green) in presence of organic vapors, is fixed onto a cleaved ended pigtail by electrostatic self assembly method. This way, when an optical signal is guided to the device head, changes in the sensing material produce variations in the reflected optical power. Standard mono mode fiber (9/125 ¿m) and a DBF laser (@ 1550 nm) have been used. Typically, wider fibers (62.5/125 ¿m) and lower wavelengths (laying in the visible spectral) are used to measure the effect of color change, but working at 1550 nm makes easier multiplexing several optical signals. A sensor was implemented and exposed to saturated concentrations of several VOCs, registering a change in the reflected optical power, especially significant for acetic acid.