The invention relates to a portable reflectometer and to a method for characterizing the collector mirrors used in solar power plants for the in-field characterization of reflection coefficients. The equipment includes all of the components required for this measurement, such as a module to measure the reflection coefficient of the mirror, an electronic data acquisition and processing system, a system for processing data and controlling the equipment, a system for storing the data of interest, a user interface system, and a system allowing communication between the aforementioned systems and an outer casing. The equipment can be used to characterize the specular reflection coefficient of flat or curved mirrors of different thicknesses, without requiring adjustments to be made to the equipment, minimizing the influence of diffuse reflection on the measurement.

The computer readable memory has recorded thereon instruction code for execution by a computing device for use with an optical power loss measurement (OPLM) system. The instruction code generally comprises: code for displaying a first set of instructions including measuring a first power value of test light outputted from a first reference optical waveguide; code for displaying a second set of instructions including measuring a second power value of test light outputted from a reference waveguide link including the first reference optical waveguide connected in series to a second reference optical waveguide; code for displaying a third set of instructions including measuring a reference power value of the OPLM system resulting from the propagation of light from via the reference waveguide link; and code for determining a corrected reference power value based on the reference power value and on the first and second power values.

In this invention, a novel technique is introduced to measure chromatic dispersion (CD) in optical fibers. This technique is based on a relatively low-frequency optoelectronic oscillation (OEO) to provide fast, precise and low-cost method for CD measurement that can be implemented easily in commercial instruments. The proposed setup is implemented to measure the CD in normal single mode fibers with lengths of 40 km, 10 km, 1 km. Moreover, it is implemented to measure CD in 400 in of nonzero dispersion shifted fiber to test the system ability to resolve small chromatic delays. The proposed setup can resolve delays less than 0.1 ps/nm (which can be further improved by increasing the oscillation frequency) and measure CD with precision as low as 0.005 ps/nm.km as low as 20 seconds over a wavelength range from 1500 to 1630 nm. Further improvements may be possible by slightly better system design.

The output profile of light from a multimode optical fiber is determined using a geometrical optics approach where the rays launched into the fiber conform to LP-modes of the fiber. This output profile can then be employed as an input to a second fiber to calculate the transmission losses of a coupler that introduces various coupling inaccuracies, such as lateral offset, axial offset, and angular offset.

An optical sensor (100) comprises: a holding sleeve (11); a fixed ferrule (12) fixedly mounted in said holding sleeve (11); a movable ferrule (13) movably mounted in said holding sleeve (11), a predetermined distance existing between a first movable end of said movable ferrule (13) and a first fixed end of said fixed ferrule (12) in said holding sleeve (11); a reflection part (14) arranged at a second movable end of said movable ferrule (13) opposite to said first movable end, for reflecting light entering the movable ferrule (13); and an actuation part (15), said actuation part (15) being constructed to drive said movable ferrule (13) to move so that said first movable end moves towards said first fixed end. An optical sensor assembly and a monitoring device comprising the optical sensor (100), or another sensor (1012) can remotely detect a mechanical movement in a passive mode. A first reflector (14, 1016) is configured to provide a first reflected optical signal. The sensor (100, 1012) is connected to the first reflector and has a first position and a second position, the second position configured to attenuate the first reflected optical signal more than the first position. The sensor is configured to move between the first and second positions in response to a monitored parameter (1018).

An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.

A rain and fog testing apparatus, comprising a fluid channel that runs between a first fluid shutoff coupler and a second fluid shutoff coupler and has at least one dispersion head fluidly coupled to the fluid channel. A liquid pump can be fluidly coupled to the fluid channel at an output end. A liquid heater may also be fluidly coupled to the system along with a controller that provides electrical control of the first fluid shutoff coupler, the second fluid shutoff coupler, the dispersion head, the liquid pump, and the heater. Further, the second fluid shutoff coupler is capable of fluidly coupling a first fluid channel to a plurality of fluid channels and the controller can adjust the orientation of the first fluid shutoff coupler, the second fluid shutoff coupler, the dispersion head, the liquid pump, and the liquid heater to create a simulation of a plurality of rain or fog events.

A rain and fog testing apparatus, comprising a fluid channel that runs between a first fluid shutoff coupler and a second fluid shutoff coupler and has at least one dispersion head fluidly coupled to the fluid channel. A liquid pump can be fluidly coupled to the fluid channel at an output end. A liquid heater may also be fluidly coupled to the system along with a controller that provides electrical control of the first fluid shutoff coupler, the second fluid shutoff coupler, the dispersion head, the liquid pump, and the heater. Further, the second fluid shutoff coupler is capable of fluidly coupling a first fluid channel to a plurality of fluid channels and the controller can adjust the orientation of the first fluid shutoff coupler, the second fluid shutoff coupler, the dispersion head, the liquid pump, and the liquid heater to create a simulation of a plurality of rain or fog events.

Methods and apparatus for evaluating the geometric properties of optical fiber preforms, which methods include: providing an optical fiber preform having a longitudinal axis, an outer diameter and a circumference; providing a two-dimensional pattern having a length parallel to the longitudinal axis of the preform and a width greater than the outer diameter of the preform; providing an image capturing device disposed such that the preform is aligned between the pattern and the image capturing device; rotating the preform about its longitudinal axis and acquiring a first plurality of images of the pattern viewed through the preform at at least two different points along the circumference of the preform; and determining at least one geometric property of the preform from the first plurality of images.

A method for temperature measurement includes measuring intensities of two adjacent wavelengths emitted from a heated optical fiber and calculating the thermal population distribution between associated energy levels.