A fiber loop based chemical sensor for industrial application

For electrical and chemical industry, the sensor should be capable of monitoring physical and chemical parameters from remote location. With this in mind, we developed a new chemical sensor based on fiber loop ringdown spectroscopy. The fiber loop requires a precision sensor element which can provide interaction of chemicals within the optical path of fiber loop. A side polished fiber is fabricated in-house and employed in the fiber loop for evanescent wave interaction with the chemical. For preliminary test of the sensor, different concentration of Dimethyl Sulfoxide (DMSO) is applied. The variation in ringdown time for different concentration of DMSO solution is successfully measured. A detection sensitivity of 5 × 10^-8 sec per unit change in concentration (%) is observed. This present sensing system is now very useful for industrial application.