A highly sensitive smart fiber sensor

Optical fiber sensors have been embedded in structural elements for over fifteen years in order to obtain information regarding the internal stress, strain, or temperature states of the structures. However, the degree to which the mechanical reliability and data stream integrity are maintained will strongly depend on the type of sensor being used, the measurement application, and the structural integration method. In this paper we present a fiber optic sensor that demonstrates higher sensitivity than the typical fiber Bragg grating sensor, and it is capable of monitoring the state of its own health. The sensor design uses an induced phase discontinuity in the fiber Bragg grating to create a narrow pass-band within the reflection spectrum of the grating. The position of this narrow window within the Bragg spectrum is used to monitor the sensor's health.