A novel concept for an intrinsic relative humidity (RH) sensor that uses polyimide-recoated fiber Bragg gratings is presented. Tests in a controlled environment indicate that the sensor has a linear, reversible, and accurate response behavior at 10–90% RH and at 13–60°C. The RH and temperature sensitivities were measured as a function of coating thickness, and the thermal and hygroscopic expansion coefficients of the polyimide coating were determined.
© 2002 Optical Society of America
Pascal Kronenberg, Pramod K. Rastogi, Philippe Giaccari, and Hans G. Limberger, "Relative humidity sensor with optical fiber Bragg gratings," Opt. Lett. 27, 1385-1387 (2002)