Abstract: A laser diode gas sensor for the spectroscopic measurement of a gas sample, with a retroreflector and a concave mirror, which define between them an open measuring path with the gas to be analyzed. Laser light passes through the measuring path, is reflected at the retroreflector, and is directed toward a detector via a concave mirror in order to determine the mean concentration of the gas component to be analyzed in the optical measuring path. Optical elements, such as beam splitters, lenses, etc., which lead to losses of intensity, were used before to couple the laser light into the beam path onto the retroreflector, and to decouple the reflected light to the detector. An improved optical imaging array, which minimizes losses, is provided. The concave mirror is provided centrally with an opening transparent to the laser light, through which a weakly divergent bundle of laser light is directed onto the retroreflector, so that the retroreflector is illuminated essentially over its entire surface.

Abstract: An improved backward Brillouin scattering optical time domain reflectometry (OTDR) device is provided which is capable of detecting the deterioration of or anticipating the fracture in an optical cable or optical fiber and measuring the position of the failure part with high resolution. To accomplish this, the OTDR constantly or periodically supplies an optical pulse having a power level of +8 dBm or higher from an optical pulse generator 20 to an optical cable, monitors a power ratio between the optical pulse supplied to the optical cable and a reflected pulse by an optical power comparator 40, detects correlation between the supplied optical pulse and the reflected pulse by a correlation detector 27 while switching the supplied optical pulse to a pseudo random optical pulse, and calculates the failure position of the optical cable when the factor of correlation shows the maximum value.

Abstract: A grating drive apparatus for use in a multiple-grating spectrometer is provided. The spectrometer has an entrance slit, an exit port, an optical path between the entrance slit and the exit port, and a plurality of diffraction gratings. Each of the gratings is rotatable about a respective preferred axis for selecting a wavelength during spectrometer operation. The grating drive apparatus includes a turret having a plurality of gratings mounted on it, a mechanical stop assembly, and a drive assembly. The drive assembly causes the turret to engage the stop assembly to rotate the turret and select a grating. The drive assembly also rotates the selected grating to select an operational wavelength.

Abstract: A device for testing multi-fiber optical cables includes a number of test stations into which an end of a cable under test is plugged. Some to the test stations provide for the attachment of an array connector, while others provide for the attachment of a number of discrete connectors. The optical input/output port of an OTDR unit is connected to each of the test stations through an optical switch, which connects this port with only one such station at a time. Within each station, signals from the optical switch are divided among a number of light paths by a splitter, which also returns signals from these light paths to the OTDR through the optical switch. The various light paths within each station include fiber optic jumpers which vary in length, so that a single test pulse from the OTDR is reflected back from a number of interfaces in the cable under test as a train of pulses.

Abstract: Fiber optic devices are tested using an optical switching assembly having two optical switches and optical junctions, each optical junction connects an optical fiber from each of the switches to an external optical fiber lead. Each switch is connected to an optical device, for example a laser or a detector, and selectively establishes an optical path between the corresponding optical device and one of the junctions. Hence, a fiber optic device may be tested by connecting the ends of the fiber optic device to respective junction leads, and selectively switching the optical paths to determine the different optical characteristics of the fiber optic device. Calibration devices may also be connected to the leads of unused junctions to check for calibration accuracy and to detect variation in optical performance over time.

Abstract: Compact triaxial multioscillator configurations are based upon frames of rhombic dodecahedron and truncated octahedral shapes as taught by U.S. Pat. No. 4,795,258. Three non-planar cavities, each comprising four intersecting bores, intersect within the frames. External Faraday rotator assemblies comprising reverse mirrors and associated permanent magnets in differing configurations eliminate the need for intracavity elements to obtain nonreciprocal splitting. In the rhombic dodecahedron-shaped frame, external Faraday rotator assemblies are fixed to three planar faces at each of which pairs of segments of each of the internal nonplanar cavities converge. In the truncated tetrahedral frame, a single external Faraday rotator assembly is fixed to the single planar face at which pairs of segments of the three nonplanar cavities converge in a pattern forming the apexes of a centered equilateral triangle.

Abstract: Disclosed is an apparatus for fluidic separation systems comprising a microfabricated conduit including a usefully long optical pathlength. The provision of a usefully long optical pathlength in the apparatus greatly improves the sensitivity of detection of separated analytes without compromising the resolving power of the apparatus.

Abstract: An optical time domain reflectometer suitable for determining its front panel insertion loss comprises a four-port coupler having first and second ports connected to a light source and an optical detector, respectively, and third and fourth ports connected to a front panel connector and a reference reflector, respectively. In use, a fiber-under-test is connected to the front panel connector. The coupler splits light from the light source between the front panel connector and the reference reflector and couples light returning from the front panel connector and reflector to the detector. The optical path between the front panel connector and the coupler is longer than the optical path between the reference reflector and the coupler by such a distance that a Fresnel reflection pulse from the reference reflector, produced by a pulse emitted by the light source, will be received by the detector before a corresponding reflection pulse returned from the front panel connector.

Abstract: Automatic measurement of the quality of each splice (17) in an optical fiber (12) is accomplished by a combination Automatic Time Domain Reflectometer and Optical Switch unit (18) situated at one of the fiber remote from the location (16) where the splice is made. Technicians at the splice location (16) control the combination Automatic Time Domain Reflectometer and Optical Switch unit (18) by launching commands thereto via a laptop computer (32) that are communicated across a wireless communication channel via a wireless transceiver (30). Fiber loss measurements made by the combination Automatic Time Domain Reflectometer and Optical Switch unit (18) are relayed to the technicians at the remote splice location across the wireless channel for processing on the computer (32) to determine the splice quality.

Abstract: There is provided a high precision device for measuring the color of non-self-luminous or self-luminous objects having interchangeable optical geometries for conversion from one optical geometry to another. The device interchanges a plurality of modules, each having at least one optical geometry for directing illumination from an illumination source and for collecting sample light reflected from a measured object or sample. Such optical geometries include a 45/0 geometry, sphere geometry, specular included geometry, and specular excluded geometry. Each module is removably attached to the device when measurement of the color of the sample is desired and may be separated from the device when measurement of the color of the sample is not desired. Also, each module may include removable filters for absorbing certain types of light, such as ultraviolet visible light, and blocking elements to determine the source of any reference signal.

Abstract: An apparatus for stabilizing the light output frequency of each laser diode for pulse light and probe light for measuring the distribution of strain, by controlling the change of the light output frequency of the laser diode due to external causes by input current of the laser diode. The apparatus is constructed such that the frequency variation of the laser diodes is detected to then generate a signal corresponding to the variation. Then, the signal is fed back to a temperature-current controller to be used as the input current signal of the laser diode.

Abstract: A zoom lens is provided between the sample and the slit of a spectrophotometer to change the size of the image of the sample on the slit plane. The picture of the sample is taken by the zoom lens and is shown on a display screen, on which a window is superimposed. When the operator changes the location of the window, the sample is moved accordingly, and when the operator changes the size of the window, the focal length of the zoom lens is changed, whereby the size of the measurement area is changed. By changing the size of the measurement area on the slit plane while the size of the elementary photo-sensors of a photo-detector is unchanged, the resolution of the two-dimensional spectrophotometry can be changed.

Abstract: A ring laser gyroscope having an alternating Faraday bias includes mode combining apparatus arranged to cause interference between the modes that propagate within the cavity. Signal separating apparatus separates a signal indicative of rotation of the frame from other components of the combined intensity signal. The signal separating apparatus produces two signals indicative of the light intensity in the interference pattern of the combined modes. These two signals have a 180.degree. phase difference in corresponding components that are dependent upon the geometric bias caused by the non-planar optical path to produce a rotation signal that is independent of the spatially uniform interference fringes caused by the geometric bias.

Abstract: A method of forming ferroelectric domain regions in a ferroelectric crystal cut so that the polarization direction is in the plane of the crystal and is along the z direction is disclosed. The method includes forming a conductive ground electrode on the surface of the plane and having an edge perpendicular to the z direction or the polarization direction in the crystal plane; and electron beam bombarding the plane of the crystal in particular spots to deposit a charge such that the electric field created between the edge of the electrode and the spots is in a direction opposite to the crystal polarization direction and causing the inversion of the crystal polarization direction between the charge spot and the electrode.

Abstract: The invention relates to a scanning device (1) for measuring physical properties of a moving fibrous web (2) which has two longitudinal edges and is intended to run in a predetermined path of movement past or through the scanning device (1). The device (1) has a carriage (11) carrying a scanning head (14). The carriage (11) is movably supported for movement transversely to the direction of movement of the web (2). A drive (12) is provided which imparts to the carriage (11) a reciprocating movement from one edge side of the web (2) to the other, during which the scanning of the web (2) is carried out. The scanning device (1) is fitted with means (21, 31, 32, 33, 36) associated with the carriage for providing, in essentially the same plane as the predetermined path of movement of the web (f), a planar web supporting surface at locations between the carriage (11) and the two longitudinal edges of the web (2) during passage of the web (2) past the scanning device (1).

Abstract: A fluorescence spectrometer for determining a concentration of a photosensitizing drug in a patient, for PhotoDynamic Therapy treatment of the patient by a treatment light at a treatment light wavelength, the fluorescence spectrometer comprising a light source that directs an interrogation beam at a blood or blood plasma sample at an interrogation wavelength range bluer than the treatment light wavelength, measuring a magnitude of an emission signal at the treatment light wavelength, the emission signal caused by the irradiation of the sample, and comparing the measured magnitude to a magnitude/concentration calibration curve to determine the concentration of the photosensitizing drug. A CPU controls the components and makes the comparison and determination.

Abstract: Apparatus for detecting defects in a web of textile material as it is being drawn through an inspection zone. A header is arranged to project a line of light on the running web and a reflected light image from the web is sensed and analyzed for defects. The header includes a fiber bundle for producing a line of light and an optical element for collimating the light upon the web as it passes through the inspection zone.

Abstract: Provided is a novel method for wavelength stabilization in a laser spectrometer useful in spectroscopic measurement. According to the method, an initial scan is performed which comprises applying a current or voltage signal to a laser. In the scan, a current or voltage signal value is increased incrementally from a minimum signal value to a maximum signal value over a predetermined total number of signal values. The minimum and maximum signal values are selected such that an absorption feature of a species to be measured falls within the scan bounded by the minimum and the maximum signal values. The relative position of the absorption feature is determined with respect to the applied signal values in the previous scan by analysis of detector outputs corresponding to the signal values in the previous scan. An absorption value corresponding to the absorption feature is determined, and the concentration of the species to be measured can optionally be calculated.

Abstract: A potted sensor coil for a fiber optic gyroscope includes an inter-layer stress relief layer of lubricating material. The coil is wound into a known pattern. Various coil configurations can be realized in which a coating layer of lubricant relieves stressing at the interface between the outer jacket of the fiber and the coil potting material.

Abstract: An electro-optical system is devised for scanning a color document into electrical signals for reproduction of the color document. The electro-optical system comprises a white light source for generating a beam of white light for illuminating the color document being scanned. A self-focus lens array consisting of at least a first row, a second row, and a third row of rod lenses is used to focus the reflected light from the color document onto a linear photosensor array. To separate the reflected light into RGB components, a first strip of red filter film is attached to one end of the first row of rod lenses; a second strip of green filter film is attached to one end of the second row of rod lenses; and a third strip of blue filter film is attached to one end of the third row of rod lenses. The light passing through the self-focus lens array causes the linear photosensor array to generate electrical signals representative of the amounts of the red, green, and blue components in the reflected light.