Sensitivity-enhanced temperature sensor based on metalized optical fiber grating for marine temperature monitoring

A sensitivity-enhanced temperature sensor for marine monitoring based on fiber Bragg grating (FBG) has been proposed and experimentally investigated. The temperature sensor has been realized by electroplating a copper coating on a metalized FBG. Then, the coated FBG is packaged by a carbon film, which protects the copper coating from being corroded when the sensor is used in the ocean. The carbon film is fabricated with magnetron sputtering. Analyses have been made to prove that the carbon film is compact and contains some diamond. This carbon film containing some diamond is called diamond-like carbon. In this way, the coated FBG will have a high temperature sensitivity of 21.86 pm/ °C. The coated FBG sensor has been tested in a simulative environment which is similar to the ocean environment. Experimental results show that the sensor maintains stable in more than 38 days.