An apparatus for measuring a length of an optical resonant cavity includes a frequency tunable light source, a beam splitter, a frequency modulator and an optical resonant cavity. The frequency tunable light source emits a beam. The beam splitter is disposed on the optical path of the beam for dividing the beam into a first beam and a second beam. The frequency of the second beam is modulated by the frequency modulator to differ from the frequency of the first beam by a beat frequency. The optical resonant cavity is disposed on the main optical path of the first beam and the main optical path of the modulated second beam. The first beam and the modulated second beam enter the optical resonant cavity for measuring a length of the optical resonant cavity, and a variation in cavity length is calculated from the beat frequency.

A high-durability and long-scale-distance fiber grating sensor and a manufacturing method therefor, which relate to the technical field of fiber grating sensors. A fiber grating is disposed on the middle segment of a commercial optical fiber. A bushing, a woven fiber jacket layer, and a packaging structure are disposed on the periphery of the commercial optical fiber. The commercial optical fiber and the bushing therebetween are fixed by using fixing points in the bushing. Anchoring segments are disposed between the fixing points in the, bushing and the woven fiber jacket layer. Two ends of the commercial optical fiber are sequentially connected to optical fibers on the anchoring segments and connecting optical fibers. Tail ends of the connecting optical fibers are connected to a transmission cable by using connecting flanges. By using the apparatus and the manufacturing method, the applicability and the durability of application of the fiber grating sensor in the civil traffic engineering field are improved, thereby providing a stable and reliable apparatus for long-time detection and sound monitoring of large engineering structures in the civil traffic engineering field.

Methods and apparatus are described for repairing a damaged area of an airplane fuselage made from fiber-reinforced composite material. In one embodiment, an intelligent patch is provided comprising a first electronic communication device to communicate information from at least one sensor regarding the presence of compression induced microfractures within the patch.

A disclosed example embodiment includes a system of testing slickline cable integrity. The system includes a composite slickline cable including a fiber reinforced polymer having at least one optical fiber disposed therein. At least a portion of the optical fiber is placed in axial stress. An optical analyzer is optically coupled to the optical fiber. The optical analyzer is operable to send an optical signal into the optical fiber, receive optical feedback from the optical fiber, responsive to the received optical feedback, identify variations in at least one parameter of the optical fiber and determine whether any identified variations exceeds a predetermined threshold, thereby indicating possible loss of composite slickline cable integrity.

In some embodiments, a distributed nondestructive inspection method for slickline cable structural defect detection transmits a light pulse along an optical waveguide in the slickline cable. A reflected light signal is 5 received from the optical waveguide in response to the light pulse. Defects can then be determined in the slickline cable based on variations in scattering intensity, phase shift, specific spectral signature, power spectral density, strain amplitude, and/or transmission loss of the reflected light signal as compared to the light pulse.

A system for monitoring a fiber-reinforced composite component in production or in service. The system includes a composite component having reinforcing fibers which are encompassed by a matrix material; at least one optical fiber arranged to extend in a continuous path over a monitoring area of the composite component for contact with the matrix material; a signal generator configured to transmit an optical signal along the at least one optical fiber; and a detector device configured to detect scattering, and in particular backscattering, of the optical signal transmitted along the at least one optical fiber.

An optical coupling between optical components and, more particular, to an optical probe configured for optical testing of at least one micro-optical component, a method for producing an optical probe, and a method for optical testing of at least one micro-optical component. The optical probe includes a probe head, wherein an optical performance of the probe head is calibrated and wherein the probe head includes a testing circuit, wherein the testing circuit is fixed on a mechanical support; at least one micro-optical element, wherein the micro-optical element is a separate element with regard to the testing circuit and in mechanical contact with the testing circuit, wherein the micro-optical element is configured to optically couple light between the testing circuit and the micro-optical component, thereby being configured to determine an optical performance of the micro-optical component.

To suppress expansion of damage to a working-state cable due to work being continued without detecting breakage of the working-state cable when the breakage occurs, the working-state cable protection monitoring system is provided with: a working means that moves or installs a wire cable-shaped construction material including an optical fiber having at least one core; an interrogator that acquires environment information about each position of the construction material, sensed by the optical fiber; and an abnormal event detection means that, when the environment information acquired at each position of the construction material satisfies an abnormal pattern, detects an abnormal event at the position, where in the working means stops movement and installment of the wire cable-shaped construction material when the abnormal event has been detected.

The present invention discloses a distributed continuous high-accuracy bidirectional displacement fiber-optic measurement system and a measurement method thereof for measuring displacement of a measurement target, including a Brillouin analysis device connected with an optical fiber strain gauge, a fiber-optic sensor assembly including a reference fiber-optic sensor device and a plurality of fiber-optic sensor devices, and an operation module, the operation module is operable to receive the continuous data and the single-spot data transmitted from the Brillouin analysis device and the fiber-optic sensor devices, and to calculate an accurate displacement for each interval of the optical fiber strain gauge according to the continuous data and the single-spot data so as to form continuous displacement data. Thus, the present invention is economic in respect of cost and suits the need of the market application, and can be applied in a large area, and enhances the accuracy of measurement.

In some embodiments, optical fiber monitoring may be facilitated. In some embodiments, monitoring of an optical fiber may be performed via a detection system to detect changes in the optical fiber that are indicative of one or more events. During the monitoring, a monitor signal may be transmitted along the optical fiber via a light source, where the monitor signal is received by the detection system as light from the optical fiber. While the detection system continues to receive light from the optical fiber in connection with the transmitting of the monitor signal, a test disturbance event may be caused to occur at a predetermined location along the optical fiber via a device at the predetermined location. In response to a failure of the detection system to detect test-related changes in the optical fiber caused by the test disturbance event, a notification indicating an issue may be generated.