Abstract: An optical waveguide laser, preferably a fiber laser, has unintentionally incorporated impurities disposed in the lasing medium which upconvert a portion of the lasing radiation to radiation of shorter wavelength, thereby introducing defects in the medium which result in increased absorption due to photodarkening. Suitable rare-earth co-dopants are intentionally incorporated during the manufacture of the fiber for effectively shunting the upconversion process. The lifetime of the fiber laser is thereby increased.

Abstract: A three port filter device is formed from a thin film filter element and a pair of lensing devices. A focusing lensing device is used, with a dual-fiber termination disposed at the object plane of the focusing lensing device. A collimating lensing device is disposed between the focusing lens image plane and the thin film filter element. The third optical port is coupled to the collimated signal passing through the filter element. The focusing lens may be moved along the optical axis to modify the spacing of the dual-fiber termination image appearing at the image plane. The change in spacing results in changing the angle of incidence of the optical signal propagating toward the thin film optical element. Since the pass wavelength of the thin film element is a function of the angle of incidence, the movement of the focusing lens may be used to "tune" the pass wavelength of the thin film optical device.

Abstract: An optical switch operatively sensitive to a fluid pressure differential includes a house having an open end, a fiber optic input line, a fiber optic output line, and a fluid-proof diaphragm sealingly engaged with the housing. The diaphragm is formed from a thin elastic material resiliently stretchable between first and second switching states and supports an optical barrier within the housing for blocking the propagation of an optical signal between the fiber optic lines when the diaphragm is in one switching state and for permitting the propagation of the signal between the fiber optic lines when the diaphragm is in the other one of the switching states. For a given housing and a given diaphragm, different optical barriers may be employed to achieve different switching thresholds. As well differing optical barriers may be used to make the switch either a normally "on" switch or a normally "off" switch. Apparatus for monitoring the level of a liquid may include a plurality of such switches.

Abstract: An optical fiber bundle comprises optical fiber ribbons disposed one on the other to constitute a stack having a side formed by an edge of each ribbon and which extends in a substantially transverse direction to the ribbons. An adhesive member is placed on this side of the stack. It adheres to the lateral edge of each ribbon to bind them. It preserves the ordered structure of the bundle when the bundle is inserted into a cable jacket.

Abstract: A color adjustable light conducting apparatus is disclosed for use in combination with a standard fiberoptic illuminator having a light output port. The apparatus includes an elongate, light transmitting fiberoptic cable or other type of conductor. A fitting and a color adjuster is carried by a distal end of the cable. The color adjuster may include a filter wheel that is rotated to position a selected color filter in the cable. A fitting and a second color adjuster may be attached to a first end of the cable for interengaging the fiberoptic illuminator.

Abstract: An monolithic version of optical multiplexer/demultiplexer with an improved spectral characteristic is provided by two diffraction gratings arranged optically in tandem and with a field stop in the coupling between them, the gratings also being arranged to provide free spectral ranges differing by a factor of at least two, and having a coupling between them that carries over into the second grating information concerning the dispersion afforded by the first grating. The field stop is constituted by a pair of etched troughs arranged in the pattern of an open chevron.

Abstract: Embodiments of the invention include an optical fiber system and method for separating the different wavelengths of transmitted light transmitted therethrough and for monitoring the respective optical power in the separated spectral components. More specifically, embodiments of the invention scan or modify the physical parameters of in-fiber gratings that couple light between spatially different modes of light within a wavelength-division-multiplexed (WDM) optical fiber system, separate the spatial modes using a mode-discriminating device (MDD) and monitor or detect the separated spectral components using a conventional or other suitable detector. By scanning the in-fiber gratings, the peak wavelength of coupling between two dissimilar modes is modified, thus allowing control of the coupling within the fiber optic system. Scanning the grating is performed, e.g., by changing the temperature or modifying the physical dimensions of the grating.

Abstract: An optical device which can be fabricated without any axial alignment by optical measurement and can therefore be produced at a remarkably decreased cost, and which is composed of an optical waveguide part (1) obtained by perpendicularly cutting an optically-transparent polymer film having a glass substrate attached thereto and having a refractive index distribution formed, in a predetermined position measured from the position of the refractive index distribution as a reference, and a holder part (2) for holding the optical waveguide part (1) in a predetermined position, the holder part (2) having a horizontal guide surface (2H) and a vertical guide surface (2V), the optical waveguide part (1) having a glass substrate surface or a polymer film surface coherently attached to the horizontal guide surface (2H) of the holder part (2), and the optical waveguide part (1) having a perpendicularly cut surface coherently attached to the vertical guide surface (2V) of the holder part (2).

Abstract: A modal evolution coupler having a low-loss or non-loss effect when a transmitted light passes through an optical fiber and is output via an expanding element, includes: a first optical fiber which gradually, thermally expands a core to evolute the mode of a transmitted light, a second optical fiber which gradually, thermally expands a core to evolute the mode of a transmitted light, an expanding element which is placed between the first and second optical fibers, and is formed of an ultraviolet curing resin, and has ends whose section areas are equal to the respective ends of the first and second expanded optical fibers when an ultraviolet ray is incident thereon and cured, and includes expanded portions which are each expanded over a predetermined expansion distance starting from a connecting portion to the first or second optical fiber and a middle portion keeping its size constant for a predetermined length between the expanded portions of the first and second optical fibers, and does not move in the expa

Abstract: A connecting device for multicore fibers includes two superposed substrates each comprising a planar optic with multiple guides so that the guides of the two substrates are disposed in parallel planes that coincide with the cores of the fiber.

Abstract: An optical fiber splicing module includes a receiving housing having a longitudinal cavity with two fiber insertion orifices through two end walls of the cavity, a fiber immobilizing member and a pressing arrangement in the cavity and a closure cap that can be clipped to the housing. The fiber immobilizing member substantially closes off the cavity and carries the pressing arrangement which is therefore received facing a groove in the bottom of the cavity and aligned with the orifices. The cap can be clipped to the housing in such a way as to define two positions of the member in the cavity, for allowing the fibers to pass and for immobilizing them in the groove.

Abstract: The invention is a temperature compensating structure for a fiber Bragg grating (FBG) contained in optical fiber. The structure comprises two plates made of materials having different temperature coefficients of expansion and bonded together. The optical fiber is bonded to the exposed surface of the plate having the lower temperature coefficient. The structure bends with changes in temperature and produces an elongation of the fiber with decreasing temperature.

Abstract: A triaxial cable for connecting a digital video camera with other video equipment is provided with optical fibers embedded in an insulating layer between two electrical conductors of the cable. The cable and associated connectors are electrically compatible with cable systems using kingstype conductors. A camera adapter and camera control unit are provided with means for communicating video signals both as digital signals along the optical fibers and as analog signals along the electrical conductors.

Abstract: An optical slip ring system (1) has a rotor interface (2) which can bolt on to a high speed rotor in a modular manner. The rotor interface (2) has circular circuit boards (7) containing the necessary drive circuits and power supply circuits for transducers mounted on the rotor. The drive circuit on the boards (7) drive three rings of emitter LEDs (9). The drive is frequency modulated and there are a number of transducers associated with each ring of emitter LEDs (9). These signals are frequency division multiplexed to ensure real time processing takes place. A fixed support (3) has a single receiver LED (15) associated with each ring of emitter LEDs (9). Contactless power is provided by an inductive power supply having a primary winding (16) on the fixed support bracket (3) and a secondary winding (10) on the rotor interface (2).

Abstract: A structure and method are provided to improve stability and performance of multiplexers in dense WDM applications. A wavelength division multiplexer (WDM) utilizing an unbalanced Mach-Zehnder Interferometer has first and second fused-fiber couplers cascaded together by two optical connecting fibers having different optical path lengths. The different path lengths can be attained with connecting fibers of two different lengths or two different refractive indexes. In some embodiments, a portion of a fiber with a different refractive index than either or both connecting fibers is fuse-spliced between a connecting fiber to provide the path length difference. Tension can be applied to the fused-fiber multi-window WDM to obtain the desired passband prior to mounting the WDM within a supporting substrate for protection. A passive thermal compensation technique can be used to minimize the thermal effect on the passband wavelengths for dense WDM applications.

Abstract: Monitoring of the wavelength and power in an optical network is realized by including a wavelength router in which output ports at particular locations are included to derive samples for the monitoring. A periodic variation in the optical length of the arms of the grating in the router is used to focus additional power at these selected locations. Such a router can also be used for multiplexing and demultiplexing optical signals.

Abstract: A fiber optic connector comprises a housing (4) retaining a ferrule assembly (1). The ferrule assembly (1) comprises a generally tubular rear portion defining a rear passage (11) along a longitudinal axis (20) of the ferrule assembly (1). A clamping insert (12) and a sleeve (13) are disposed within the rear passage (11). The sleeve (13) telescopically receives the insert (12) and exerts a radial force on the clamping insert (12) to align and retain a terminating fiber.

Abstract: An optical sensor having at least one long period grating disposed within an optical waveguide is provided. The optical waveguide has a refractive index profile. The long period grating has a plurality of index perturbations spaced apart by a periodic distance .LAMBDA.. The long period grating promotes an excitation of confined propagating broadband light into higher order modes that excite a sensing mechanism. The excitation of confined propagating broadband light is spectrally dependent on the periodic distance of the long period grating and the refractive index profile of the optical waveguide.

Abstract: An RF optical signal processing system that can provide various filter functions by way of tapped delay lines with fiber Bragg gratings, variable weight taps, positive and negative taps and a short coherent length optical source. Such an RF optical signal processing systems is advantageous over corresponding RF electronic systems and offer the increased bandwidth and lower power consumption making the RF optical signal processing system suitable for various application such as avionics and satellite communications.

Abstract: A gas or vapor permeable optical fiber waveguide with a liquid core is employed as a probe for the detection or measurement of a chemical specie of interest by filling the waveguide core region with a reagent liquid which undergoes a change in an optical characteristic thereof when exposed to the chemical specie and then inserting the filled waveguide into an environment in which the chemical specie may be present. The chemical specie, if present, will permeate through the waveguide wall and react with or be absorbed in the core liquid. Sensitivity is enhanced by controlling the pressure differential across the waveguide wall and/or by shaping the waveguide to enlarge the surface area. When the reaction generates light, the devices which detect that light will be shaped and disposed to maximize the collection thereof.