Abstract:
A two-core optical fiber is provided for use in Brillouin distributed fiber sensor applications and systems. The two-core fiber includes a first and second core. Each core is configured to exhibit a Brillouin frequency shift greater than 30 Mhz relative to the other core. Further, each core possesses temperature and strain coefficients that differ from the other core. The cores can be configured to produce Brillouin frequency shift levels of at least 30 Mhz relative to one another. These differences in shift levels may be effected by adjustment of the material compositions, doping concentrations and/or refractive index profiles of each of the cores. These optical fibers may also be used in BOTDR- and BOTDA-based sensor systems and arrangements.
Abstract:
An apparatus (01) configured for identifying numbers for layers having objects thereon within a container (02), the objects being accommodated in the container and arranged in layers. the apparatus comprising: an optical fiber sensor (10) configured for detecting presence or absence of the objects from layers within a detecting range; a support frame (20) configured for carrying the optical fiber sensor (10); a guide rail (60) configured for defining a moving direction of the support frame (20); a motor (40) and driving mechanism (30) configured for driving the optical fiber sensor to move along the guide rail; and a controller (50) connected with the optical fiber sensor (10) and the motor (40), wherein the controller (50) is at least configured for obtaining the numbers for the layers having objects thereon according to a moving distance of the support frame (20), in the case that the presence of the objects is detected by the optical fiber sensor (10). In the case of a smaller spacing between the layers in the container (02), the apparatus (01) can accurately obtain the number for the layer in which an object locates, so that a robot arm can take out the object placed at this layer directly. The object is a display panel.
Abstract:
Methods and an optical interrogation system for monitoring structural health of a structure are provided. The method includes generating an optical signal using an optical signal generator, and directing the optical signal towards at least one optical sensor located remotely from the optical signal generator. The optical sensor includes a photonic crystal wafer optically interacting with the optical signal and an environmental condition. The method also includes capturing, by an optical signal receiving apparatus, a reflected optical signal reflected from the at least one optical sensor, and analyzing the reflected optical signal to determine a change in the environmental condition.
Abstract:
Fiber optic sensors include sensor regions in which an optical phase is modulated by an analyte to be detected. A long period fiber grating (LPG) is coupled to a coating that is arranged to selectively interact with the analyte. The resulting phase change is detected based on a transmission spectrum associated with the LPG so that analyte is detected and quantified. A plurality of such sensors is distributed along a fiber to form a sensor array that can be situated to detect analyte at a plurality of discrete regions.
Abstract:
A fiber-optic sensor can have a Michelson sensor portion and a Mach-Zehnder sensor portion. A first splitter-coupler can be configured to split incoming light between a first fiber portion and a second fiber portion. A first polarization-phase conjugation device can be configured to conjugate a polarization phase of incident light corresponding to the first fiber portion, and a second polarization-phase conjugation device can be configured to conjugate a polarization phase of incident light corresponding to the second fiber portion. Each of the first and second polarization-phase conjugation devices can be configured to reflect light toward a detector and through the respective first and second fiber portions. A coupler can be configured to join light in the first fiber portion with light in the second fiber portion, and a third fiber portion can be configured to receive light from the coupler and to illuminate a second detector.
Abstract:
A fiber optic sensor interrogation system with inbuilt passive power limiting capability that provides improved safety performance for use in explosive atmospheres.
Abstract:
An optical system for sensing an environmental parameter, comprising: an optical pulse generator for generating an excitation pulse; a pulse splitter for splitting the excitation pulse into a sensing pulse and a reference pulse; a sensing arm for receiving the sensing pulse, the sensing arm comprising an emission sensor for sensing the environmental parameter, the optical emission sensor generating a first measurement pulse having a measurement wavelength; a reference arm for receiving the reference pulse, the reference arm comprising an emission artefact adapted to convert the reference pulse into a second measurement pulse having the measurement wavelength; a time delay line for delaying a relative propagation of the measurement pulses; a light detector for measuring an optical energy of the first and second measurement pulses; and an optical link for optically connecting the pulse generator to the pulse splitter, and the sensing and reference arms to the light detector.
Abstract:
An optical system for sensing an environmental parameter, comprising: a pulse generator for generating a first pulse having a first wavelength and a second pulse having a second wavelength; a pulse splitter for splitting each one of the first and second pulse into a sensing pulse and a reference pulse; a sensing arm for receiving the sensing pulses therefrom and comprising a spectro-ratiometric sensor; a reference arm for receiving the reference pulses; a time delay line for delaying a relative propagation of the sensing pulses and the reference pulses; a light detector for measuring an optical energy of the sensing pulse and the reference pulse, for the first and second wavelengths; and at least one optical link for optically connecting the pulse generator to the pulse splitter, and the sensing and reference arms to the light detector.
Abstract:
A reflective element for directing an optical signal into a fiber optic sensor having an optical fiber includes a plane containing a sharply defined straight line that separates between a first area of low reflectivity and a second area of high reflectivity. The plane is disposed parallel to a free end surface of the optical fiber so that the free end surface intersects the line of the reflective element, whereby relative movement between the free end surface of the optical fiber and the line in response to a physical change sensed by the fiber optic sensor induces variations in an optical signal reflected by the reflective element through the optical fiber, which variations allow measurement of the physical change.
Abstract:
An invention for making productive uses of normally undesirable whiskers is provided. Embodiments of the invention include a variety of apparatuses and methods associated with forming and using whiskers as well as forming whisker compounds is disclosed. For example, whisker detection modules can be created which provide a whisker surveillance capability. The whisker detection modules can further be coupled with a whisker response system such as an alarm or insulating material dispersing system. Another aspect of the invention is providing a variety of environments or microenvironments with regard to a whisker forming structure to affect whisker creation such as maximizing whisker formation. Another example includes provision of a variety of embodiments for manufacturing compounds of whiskers of various metal and metal alloys, including structures and methods is provided. Whisker compounds produced using various embodiments of the invention can be used for various applications.