Abstract: A fiber chuck comprising a rod made of a vitreous material having a fiber groove for an optical fiber. The optical fiber lies in the fiber groove, and a clamping mechanism holds the optical fiber in place. The fiber holding chuck positions the optical fiber without damaging the fiber in order to align the fiber with another fiber. The clamping mechanism maintains the position of the aligned fiber. Preferably, the fiber chuck mounts in a chuck groove of a chuck mounting fixture. The chuck mounting fixture can attach to a fiber positioning mechanism, and the positioning mechanism positions the chuck mounting fixture along with the fiber chuck and the optical fiber to align and splice two optical fibers together while reducing the risk of damage to the optical fibers.

Abstract: A fiber holding chuck comprising a silica glass rod having a fiber groove or fiber chuck for an optical fiber. The optical fiber lies in the fiber groove, and a clamping mechanism holds the optical fiber in place. The fiber holding chuck positions the optical fiber without damaging the fiber in order to align the fiber with another fiber. The clamping mechanism maintains the position of the aligned fiber. The fiber chuck mounts in a chuck groove of a chuck mounting fixture. The chuck mounting fixture attaches to a fiber positioning mechanism, and the positioning mechanism positions the chuck mounting fixture along with the fiber chuck and the optical fiber to align and splice two optical fibers together while reducing the risk of damage to the optical fiber.

Abstract: A method of locating the azimuthal positions of the transverse axes of an optical fiber that has a cladding and a core with an elliptical cross section, where the elliptical cross section has a major axis and a minor axis and the optical fiber has a longitudinal axis. The present invention also provides a method of detecting the azimuthal position of an optical fiber from which an interference pattern generated by reflections from a coherent light beam directed onto the optical fiber in a direction transverse to the optical fiber's longitudinal axis changes symmetrically as the fiber is turned in opposite directions about its longitudinal axis. In addition, the invention provides a method to determine which axis of an optical fiber elliptical's core, the major axis or the minor axis, is orthogonally aligned with the coherent HeNe laser beam.

Abstract: An improved fiber optic rotation sensing technique and an improved optical fiber gyro are provided which exhibit increased sensitivity to and linearity of rotation measurement by using a special dual-section, counter-wound fiber coil for measuring the Sagnac phase shift resulting from rotation of the coil. The optical fiber coil has a plurality of turns and is formed of at least two separate interconnected coil sections each having a predefined number of turns of fiber. In the gyro arrangement, the separate sections are axially disposed adjacent to each other in such a way that the direction of winding of the turns in one of the coil sections is counter to the direction of winding of the turns in the other of the coil sections. The plurality of turns in each coil section is selected to be such that the sum of the effective lengths defined thereby is sufficient to realize the desired gyro modulation frequency.

Abstract: A method of forming an optical fiber joint between a pair of elongated optical fibers each of which has a longitudinal axis surrounded by a core and cladding having different refractive indices and forming a single-mode light-guiding region, the core and cladding of each fiber having non-circular transverse cross-sections defining two polarization-maintaining axes of birefringence transverse to the longitudinal axis of the fiber. Each of the fibers also has predetermined external flat reference surfaces for locating the core and cladding and the axes of birefringence within each fiber from the exterior geometry of the fiber.

Abstract: A fiber optic doppler anemometer comprises a source of coherent light, a directional coupler formed by the combination of a pair of single-mode optical fibers, and a photoelectric transducer. The first end of the first fiber receives an incident beam of light from the source and guides it through the directional coupler to the second end of the first fiber, which is located adjacent to a body of moving particles to be measured, where both the second end of the first fiber and the moving particles reflect a portion of the incident light back into the first fiber. The reflected light, which has a frequency different from that of the incident beam entering the first fiber, is directed back through the directional coupler which couples a portion of the reflected light toward the first end of the second fiber. The photoelectric transducer receives the light emerging at the first end of the second fiber and converts it into analogous electrical signals.

Abstract: A laser-optical fiber interface including the combination of a solid state laser producing a point source of polarized light and a polarization-holding, single-mode optical fiber. The optical fiber comprising a core and cladding of non-circular cross section and having different refractive indices forming a single mode guiding region which permits the de-coupling of waves polarized along the axis of the fiber. The outer surface of the fiber includes an indexing surface with a predetermined geometric relationship to the guiding region. The optical fiber being mounted upon a substrate for receiving and supporting the indexing surface of the fiber with the solid state laser so that the end of the fiber is placed and aligned adjacent the solid state laser.

Abstract: A continuously drawn optical fiber comprising a core and cladding having different refractive indices and forming a single-mode guiding region, and the outer surface of the fiber having a cross-section forming a pair of orthogonal exterior flat surfaces so that the location of the guiding region can be ascertained from the exterior geometry of the fiber, the guiding region being offset from the center of gravity of the transverse cross-section of the fiber and located sufficiently close to at least one of the flat surfaces to allow coupling to a guided wave through that surface by exposure or expansion of the field of the guiding region.

Abstract: A fiber-optic polarizer comprising the combination of an optical fiber having a polarization-holding core and cladding with different refractive indices and forming a single-mode guiding region, the guiding region being offset from the center of gravity of the fiber section and located sufficiently close to the surface of one side of the fiber, along a selected length of the fiber, to expose the evanescent field of the guiding region at the surface of the one side to allow coupling to a contiguous medium, the outer surface of the fiber having a non-circular cross-section with a predetermined geometric relationship to the guiding region and a pair of orthogonal polarization axes therein so that the location of the guiding region and the orientation of the axes can be ascertained from the geometry of the outer surface, and a coating of indium on at least the one side of the fiber where the evanescent field is exposed so that light waves having undesired polarizations are attenuated by the indium coating.

Abstract: A fiber-optic rotation sensor comprises a coil of polarization-holding, single-mode optical fiber (25) having a core (26) with a non-circular cross-section defining two transverse orthogonal axes, the outer surface (28) of said fiber having a non-circular cross-section with a predetermined geometric relationship to said orthogonal transverse axes, a laser source (30) coupled to one end of said fiber (25) for supplying said fiber (25) with an optical signal having a fixed polarization plane, said non-circular outer surface of said fiber (25) forming a reference surface (29) for precisely aligning one of said transverse orthogonal axes of said fiber core (26) with said fixed polarization plane of the optical signal from said laser source (30).

Abstract: An optical fiber comprising a core and cladding having different refractive indices and forming a single-mode guiding region, the core having a non-circular cross-section defining two transverse orthogonal axes which, in combination with the different refractive indices, permit the de-coupling of waves polarized along the axes. The guiding region is located sufficiently close to the surface of the fiber along a selected length of the fiber, to allow coupling to a guided wave. The outer surface of the fiber has a non-circular cross-section with a predetermined geometric relationship to the guiding region and the orthogonal transverse axes so that the location of the guiding region and the orientation of the axes can be ascertained from the geometry of the outer surface.

Abstract: A method of making an optical fiber, comprising the steps of forming an optical preform having a core and a cladding with different refractive indices, the core being offset from the geometric center of the preform and having a non-circular cross-section defining two transverse orthogonal axes, the core having a longer transverse dimension along one of the orthogonal axes than along the other of the axes for guiding two fundamental modes, which, in combination with the different refractive indices, permits the de-coupling of waves polarized along the axes, the outer surface of the preform having a non-circular cross-section forming an indexing surface with a predetermined geometric relationship to the core and the orthogonal transverse axes so that the location of the core and the orientation of the axes can be ascertained from the geometry of the outer surface, and drawing an optical fiber from the preform with the drawing rate and the temperature of the preform being controlled to produce a fiber with a cro

Abstract: An evanescent-field coupler for an optical fiber having a core and a cladding forming a guiding region located sufficiently close to the surface of the fiber along a selected length thereof to allow evanescent-field coupling of an optical signal from the guiding region to an optical fiber or other device outside the guiding region, the cladding consisting essentially of silica, the coupler comprising a vitreous layer of amorphous boron oxide or a boron oxide compound fused to the cladding and having an index of refraction substantially matching the index of refraction of the cladding.

Abstract: A fiber-optic polarizer comprising the combination of an optical fiber having a core and cladding with different refractive indices and forming a single-mode guiding region, the core having a non-circular cross-section defining two transverse orthogonal axes which, in combination with the different refractive indices, permit the de-coupling of waves polarized along the axes, the guiding region being located sufficiently close to the surface of the fiber, along a selected length of the fiber, to allow coupling to a contiguous medium, and the outer surface of the fiber having a non-circular cross-section with a predetermined geometric relationship to the guiding region and the orthogonal transverse axes so that the location of the guiding region and the orientation of the axes can be ascertained from the geometry of the outer surface.

Abstract: A non-linear waveguide component is formed by a pair of optical fibers disposed in side-by-side relation and defining between them a space of elliptical cross-section. A single crystal of electro-optic material is grown in situ in the space between the fibers and has major and minor crystal axes coinciding with the major and minor axes of the space.

Abstract: A dielectric waveguide comprises a wave propagating member having a core with a refractive index n.sub.1 and a cladding with a refractive index n.sub.2, the core having an elongate cross-section with a major axis a and a minor axis b. The values of n.sub.1, n.sub.2, a and b are such that only the two orthogonally polarized fundamental modes of a wave with a prescribed wavelength can propagate through the core, thereby avoiding propagation of unwanted higher order modes of the wave, and such that the group velocities of the two orthogonally polarized fundamental modes are substantially equal so that any accidental coupling between the fundamental modes does not reduce the bandwidth of the waveguide.

Abstract: An opto-electronic element consists of a dielectric optical waveguide having a single crystal core of meta-nitroaniline. The element is made by feeding molten meta-nitroaniline into a hollow fibre along which a temperature gradient exists. Nucleation sets in at one end of the fibre and the temperature gradient is altered to promote crystal growth along the fibre. The element can be used as a polarizer, in isolators, harmonic generators or mixers. The action of the device depends on either the non-linear optical properties of the meta-nitroaniline or the optical anisotropy of the meta-nitroaniline. To make a polarizer the meta-nitroaniline core is surrounded by a cladding having a refractive index lying midway between two of the refractive indices of the meta-nitroaniline.

Abstract: A system for detecting a reflected light beam includes a source of coherent light such as a laser beam, an optical fiber spaced away from the source for receiving an incident beam of coherent light from the source at one end of the fiber, means for reflecting a portion of the incident beam back through at least a portion of the fiber to radiate a reflected beam which includes narrow angle signals having a beam width corresponding to that of the incident beam and wide angle signals having a beam width substantially wider than that of the incident beam, receiving means between the source and the optical fiber for receiving the reflected beam and having an optical aperture therein for transmitting the incident beam and the narrow angle signals in the reflected beam, and a projector lens between the receiving means and the optical fiber for directing the incident beam into the optical fiber and for directing the narrow angle signals in the reflected beam into the optical aperture of the receiving means.

Abstract: An optical fiber tap for tapping optical energy from an optical fiber includes an optical waveguide positioned adjacent to the fiber for collecting light signals therefrom. The optical waveguide preferably has an index of refraction greater than the index of refraction of the fiber. A coupling material interconnects the fiber and the optical waveguide for conducting light from the fiber into the waveguide, the coupling material preferably having an index of refraction between the indexes of the waveguide and the fiber. A photodetector is coupled to one end of the waveguide for receiving light signals therefrom and converting the light signals to corresponding electrical signals. When the tap is used to remove light from the cladding of an optical fiber, pressure is applied to preselected points on the fiber upstream of the tap to couple optical signals from the fiber core into the fiber cladding.