An optical sensor and a deformation detection system in which the optical sensor is used. The optical sensor includes an optical fiber, an elongated hollow housing having an interior portion, and a material disposed on an inner surface of the housing that produces a persistent change in an optical signal transmission property of the optical fiber when the optical fiber contacts the material. The optical fiber elastically extends between opposing ends of the housing such that a bending deformation of the housing beyond a threshold radius of curvature causes a contact to occur between the material and the optical fiber. The contact results in persistent change in the optical signal transmission property of the optical fiber, which can be detected to determine whether deformation of the device occurred beyond a predetermined threshold value. The deformation detection system can use one or more of the optical sensors attached to the device.

An optical sensor and a deformation detection system in which the optical sensor is used. The optical sensor includes an optical fiber, an elongated hollow housing having an interior portion, and a material disposed on an inner surface of the housing that produces a persistent change in an optical signal transmission property of the optical fiber when the optical fiber contacts the material. The optical fiber elastically extends between opposing ends of the housing such that a bending deformation of the housing beyond a threshold radius of curvature causes a contact to occur between the material and the optical fiber. The contact results in persistent change in the optical signal transmission property of the optical fiber, which can be detected to determine whether deformation of the device occurred beyond a predetermined threshold value. The deformation detection system can use one or more of the optical sensors attached to the device.

An optical sensor and a deformation detection system in which the optical sensor is used. The optical sensor includes an optical fiber, an elongated hollow housing having an interior portion, and a material disposed on an inner surface of the housing that produces a persistent change in an optical signal transmission property of the optical fiber when the optical fiber contacts the material. The optical fiber elastically extends between opposing ends of the housing such that a bending deformation of the housing beyond a threshold radius of curvature causes a contact to occur between the material and the optical fiber. The contact results in persistent change in the optical signal transmission property of the optical fiber, which can be detected to determine whether deformation of the device occurred beyond a predetermined threshold value. The deformation detection system can use one or more of the optical sensors attached to the device.

A hydrophone has a mandrel with a shell and a cylindrical cavity inwardly adjacent to the shell. A passage provides fluid communication between the cylindrical cavity and an exterior environment surrounding the mandrel. The hydrophone further has an optical fiber having an optical sensing section that is at least partially wound on the mandrel. The optical sensing section has an optical characteristic that varies as a function of a radial dimension of the mandrel. The mandrel has a core of solid material having a bulk modulus lower than 0.1 GPa. The cylindrical cavity is between the core and the shell.

A method and a system for determining a displacement of an object are provided. The method includes: providing a predetermined modal power distribution characteristic; directing a light onto the object resulting in a reflected light; propagating the reflected light through different propagation modes, receiving a resulting modal power distribution characteristic; and comparing the resulting modal power distribution characteristic with the predetermined modal power distribution characteristic to determine the displacement of the object.

An optical encoder having diffuser members, and methods for detecting the rotational movement of the cylinder of the optical encoder are disclosed. The optical encoder may include a rotatable cylinder configured to reflect light. The rotatable cylinder may include an encoding pattern of alternating reflective stripes having distinct light-reflective properties. The optical encoder may also include a light source positioned adjacent the rotatable cylinder, and an array of optical sensors positioned adjacent the rotatable cylinder. The array of optical sensors may receive the reflected light from the rotatable cylinder. The optical encoder may include a diffuser member positioned on the rotatable cylinder, the light source, and the array of optical sensors.

A fiber optic sensor for detecting an excitation in proximity to a fiber optic assembly, the excitation inducing a modulation of the phase of an optical signal propagating in the fiber optic assembly, the sensor comprises: a laser assembly emitting at least one laser beam; a fiber optic assembly; an optical system configured to: inject at least one portion of the laser beam; generate at least one laser signal beam issued from the laser beam injected into and propagated in the fiber assembly; generate at least one reference beam from the laser beam or the signal beam; produce at least one interference zone corresponding to the interference between a portion of the reference beam and a portion of the interference signal beam corresponding to the interference between a portion of the reference beam and a portion of the signal beam; a digital holography assembly comprising: a liquid-crystal spatial light modulator; a video camera configured to receive the interference zone and to transcribe it electrically to the liquid-crystal spatial light modulator in order to create thereon a phase hologram corresponding thereto; at least one optical detector configured to detect an output optical signal beam.

A fiber Bragg grating sensor arrangement includes a resonant cavity light emitting diode for outputting light; a fiber having a first end disposed to receive light output from the resonant cavity light emitting diode, the fiber including fiber Bragg grating etched at one or more locations along a length thereof. A strain mount or beam supports the fiber and to which the fiber is attached or bonded. A light detection circuit disposed at a second end of the fiber receives light traveling through the fiber, the light detection circuit sensing intensity of the received light that corresponds to strain or force applied to the fiber that is bonded to the strain mount. Another fiber Bragg grating sensor arrangement includes a second reference fiber that does not receive a force or strain. The reference fiber provides an output used to prevent temperature/humidity from affecting the output of the FBG sensor arrangement.

A method of detecting a damage of a wind turbine blade of a wind turbine rotor includes: a light input step of inputting light into a fiber-optic sensor mounted to the wind turbine blade; a light detection step of detecting reflection light from the grating portion; an obtaining step of obtaining a wavelength fluctuation index representing a fluctuation amount of a wavelength of the reflection light detected in the light detection step; and a detection step. The detection step includes detecting the presence or the absence of the damage of the wind turbine blade based on the wavelength fluctuation index taking account of a correlation between the wavelength fluctuation index of the wind turbine blade and a load index related to a load applied to the wind turbine blade, or a correlation between the wavelength fluctuation index and a temperature index related to a temperature of the wind turbine blade.

An interferometer apparatus for an optical fiber system and method of use is described. The interferometer comprises an optical coupler and optical fibers which define first and second optical paths. Light propagating in the first and second optical paths is reflected back to the optical coupler to generate an interference signal. First, second and third interference signal components are directed towards respective first, second and third photodetectors. The third photodetector is connected to the coupler via a non-reciprocal optical device and is configured to measure the intensity of the third interference signal component directed back towards the input fiber. Methods of use in applications to monitoring acoustic perturbations and a calibration method are described.