The invention provides a measurement system to interrogate at least one birefringent optical sensor and a method to interrogate birefringent optical sensors at high speed and high resolution. The system and method detects, at least, a first and a second spectral feature that are polarization dependent, wherein the detected first and second spectral features correspond to different responses of at least one birefringent optical sensor.

A system and method for dynamically calibrating a distributed fiber optic sensing system is disclosed. The calibration system includes a light source for generating pulses of coherent light, an optical fiber arranged at least partly in a ground soil region to guide the light and a photo detector for detecting scattered light returning from the optical fiber in dependence of time. The method includes obtaining information from which a temporal change of an acoustic transfer characteristic of the ground soil region is derivable and calibrating a distributed acoustic sensing system based on the changed acoustic transfer characteristic.

An interferometric measurement system measures a spun optical fiber sensor that includes multiple optical cores configured in the fiber sensor. A calibration machine includes a calibration fixture having known dimensions, one or more automatically controllable actuators for wrapping the fiber sensor starting at one end of the fiber sensor onto a calibration fixture having known dimensions, and an actuator controller configured to control the one or more actuators with actuator control signals. Interferometric detection circuitry, coupled to the actuator controller and to the other end of the fiber sensor, detects measured interferometric pattern data associated with each of the multiple cores when the fiber sensor is wrapped onto the calibration fixture. Data processing circuitry determines compensation parameters that compensate for variations between an optimal configuration of the multiple cores and an actual configuration of the multiple cores in the fiber sensor based on the detected measured interferometric pattern data. The compensation parameters compensate subsequently-obtained measurement interferometric pattern data for the fiber sensor.

An aircraft measurement system includes an interrogator and an optical sensor assembly. The optical sensor assembly includes an optical sensor connected along a sensor path to the interrogator, a data storage device, and a control circuit connected along a power path to the interrogator. The sensor assembly also includes an opto-electric device for converting an optical signal to an electric current, connected along the power path between the interrogator and the control circuit, to power the data storage component through the control circuit, and a transmitter operationally connected to the control circuit and connected along a data path to the interrogator, to provide operational data along the data path to the interrogator. The data storage component provides operational data to the interrogator across the data path, and the interrogator is configured to receive sensor data from the sensor across the sensor path.

A monitoring system includes optical sensors disposed on one or more fiber optic waveguides. Each optical sensor is spaced apart from other optical sensors and is disposed at a location along a route defined by a transportation structure that supports a moveable conveyance. The plurality of optical sensors are mechanically coupled to one or both of the transportation structure and the moveable conveyance. Each optical sensor provides an optical output signal responsive to vibrational emissions of one or both of the transportation structure and the conveyance. The monitoring system includes a detector unit configured to convert optical output signals from the optical sensors to electrical signals. A data acquisition controller synchronizes recordation of the electrical signals with movement of the conveyance.

A system and technique for obtaining two or more distributed measurements from an optical sensing fiber deployed along a desired measuring path are disclosed. Interrogating probes from two or more different distributed measuring systems are combined and launched into the sensing fiber. Backscattered light generated in response to the combined interrogating probes is separated into portions and each portion is provided to a respective distributed measuring instrument. In this manner, distributed measurements corresponding to different parameters of interest, such as temperature and pressure, along the measuring path can be measured simultaneously using the same sensing fiber.

A fiber optic sensing system includes a plurality of optical probes, a light source, and a light splitting unit connecting the light source to the plurality of optical probes. The light splitting unit splits a light emitted from the light source into a plurality of divided lights, the divided lights being transmitted to the plurality of optical probes.

A spectral interrogation device, including: an optical source for emitting a light signal, a measurement optical fibre comprising a series of successive Bragg gratings for reflecting the light signal in different wavelength bands, a reflective optical fibre comprising a total reflection element, a wavelength detector, and an optical switch for switching between a sequence of three operating modes. In a first mode, the light signal emitted by a given optical source is guided from the optical source to a corresponding measurement optical fibre. In a second mode, the light signal is guided to make a predetermined number of return trips in a line formed by a coupling between the measurement optical fibre and a corresponding reflective optical fibre, generating a predetermined delay between the successive gratings. In a third mode, the light signal is guided to a corresponding detector to successively measure the wavelength bands associated with the gratings.

A method is provided for determining temperature changes of an optical fibre having Fiber Bragg Grating patterns provided in at least one portion of the optical fibre. The method involves: emitting light into the optical fibre in a first direction from a first detector arrangement, receiving reflections from the patterns of such emitted light by the first detector arrangement, and processing the reflections for determining a current temperature change related to the optical fibre; and on the basis of predetermined criteria, emitting light into the optical fibre in an opposite, second, direction from a second detector arrangement, receiving reflections from the patterns of such emitted light by the second detector arrangement, and processing the reflections for determining a current temperature change related to the optical fibre. A computer program product comprising program code for implementing the above-described method is also provided, along with an associated system and platform.

A side illuminated multi point multi parameter optical fiber sensor that requires no sensitive coating is provided. This sensor comprises an optical fiber having at least one removed cladding section as the sensitive region, at least one probing light source that side illuminates the fiber, a power supply, a detector, a signal processor and a display. The sensitive optical fiber is optically affected by the presence of a measurand medium that can fluoresce, phosphoresce, absorb and/or scatter the probing light. This probing light is guided by the fiber core towards a detector which measures the light intensity and this light intensity is correlated with a measurand.