Abstract: A fiber optic moisture sensor is described that can detect the presence or concentration of an analyte in an environment; additionally, a method for making the sensor is described. The invention consists of three primary components: a sensor head, an optical link, and a sensor readout. The sensor head contains the sensing medium, which is comprised of a superabsorbing polymer that hosts a hydrochromic material. The superabsorbing polymer attracts moisture from the environment it is sensing until an equilibrium concentration of water in the environment is obtained effectively magnifying the ability of the hydrochromic material to sense very small concentrations of moisture. An optical link allows light to travel to and from the sensor head. The sensor readout has the necessary electronics to calibrate the optical signal from the sensor head, and the ability to determine and communicate the moisture concentration in the environment being sensed to the user or process control system.