Gte Laboratories Incorporated

Gte Products Corporation

W John Carlsen

Paul Melman

Carl F Buhrer

Mark L Dakss

Alfred H Bellows

John E Benasutti

Wendell L Griffin

Barbara M Foley

Gary M Lambert

Sarah S Cousins

A method for coupling light from one or more light-emitting devices into corresponding optical fibers includes placing the light-emitting devices on the top surface of a substrate and forming, by photolithographical means, on the top surface of said substrate V-grooves for holding fibers in precise relationship with said light-emitting devices. Additionally, alignment pedestals or posts are formed on said substrate in predetermined relationship to the light emitting devices and alignment V-grooves are photolithographically formed on the top surface of said substrate parallel to said fiber V-grooves. The substrate is cleaved into two sections and said sections are assembled in orthogonal relationship with the section containing the light-emitting devices and alignment posts section being secured to the section containing the fiber and alignment V-grooves so that said posts fit into said alignment V-grooves, thereby aligning the fiber V-grooves with the light-emitting devices.

Method for coupling laser array to optical fiber array

A quasi-achromatic configuration of two nonreciprocal optical rotators coupled by linear retardation elements based on total internal Fresnel reflection, such that wavelength or temperature effects on the optical rotator elements compensate one another to give quasi-achromatic isolation and/or temperature stability when this optical configuration is incorporated into an optical isolator or circulator. A quasi-achromatic optical isolator through which a light beam within a wavelength range about a nominal wavelength may propagate is made from a sequence of elements having a first plane polarizer accepting said light beam as an input, said light beam then passing through in sequence, a first Faraday rotator, a first wavelength independent linear retardation element, a second Faraday rotator, a second wavelength independent linear retardation element, and said light beam exiting said isolator undiminished in intensity through a second plane polarizer. A quasi-achromatic optical circulator having first, second, third and fourth ports is provided such that said circulator may accept a light beam within a wavelength range about a nominal wavelength and direct it to a succeeding port. A light beam enters said circulator through a first polarizing beam splitter adjacent to said first and third ports and passes through sequentially a first Faraday rotator, a first wavelength independent linear retardation element, a second Faraday rotator, a second wavelength independent linear retardation element and a second polarizing beam splitter adjacent to said second and fourth ports of said circulator, whereby said light beam is transmitted undiminished in intensity to the next succeeding port.

Quasi-achromatic optical isolators and circulators using prisms with

A true n-by-n optical crosspoint matrix switch has n optical fiber outputs each carrying the same light that entered the switch at one of n fiber inputs, maintaining the full optical spectral characteristics although the polarization states may be modified. A mounting plate on a patch panel has an n-by-n array of connection adapters in n rows and no columns. An electromechanical positioning mechanism is utilized to position n input fibers along one row to any of n adapter positions each in a different column on a first side of said plate, and n output fibers along one column to any one of n adapter positions, each in a different row on a second side of said plate. Any input fiber can be connected to any output fiber and none of the adapters are shared by more than one input or one output connector. The electromechanical positioning mechanism includes a pair of cam driven walking legs supporting a fiber carrier one for each column on the first side of said plate and one for each row on the second side of said patch plate. The fiber carriers step linearly from one adapter position to the next, raising and lowering the fiber to break or make connections.

Optical fiber crossconnect switch

A birefringent optical wavelength multiplexer/demultiplexer includes a first polarization beam-splitter, a first reflector, a plurality of birefringent elements, a second reflector, and a second polarization beam-splitter. The plurality of birefringent elements are so oriented that each element introduces an additional sinusoidal component to the transfer function of the device that tends to effectuate a flattened transfer function.

Birefringent optical multiplexer with flattened bandpass

A centering device holds an optical fiber along an axis with three fiber receiving sections and a receiving member. The receiving member has a concentric cylindrical cavity for holding assembled sections. Each section, substantially identical, has a uniform cross-sectional configuration at right angles along a major portion of its length forming a boundary of fixed perimeter. One portion of one section contacts another section. Another portion contacts a different section. A third portion contiguous to the first two portions is adapted to engage an optical fiber along its length. A fourth portion contiguous to the first two, but not to the third, engages the cylindrical wall defined by the concentric cavity. The cavity terminates with a planar wall perpendicular to the axis. It can have an axially oriented truncated conical recess. The fourth portion of the boundary engages differing amounts of a cylindrical wall depending upon the shape of the fourth portion. The sections include elastomeric material for a passageway defined by the third portions to expandably receive an optical fiber dimensioned larger than the passageway. The passageway can have a triangular cross-section for receiving a fiber having a circular cross-section. It can flare outwardly from a position interior receiving means to respective ends thereof. Passageway flaring can have various shaped configuration. The assembled three fiber receiving sections can have a polygonal shaped external surface. The receiving member can be transparent.

Optical fiber centering device

An optical multiplexer/demultiplexer provides for arbitrarily closely spaced wavelength channels, the spacing and locations thereof being determined by the thickness of birefringent crystals such as, for example, quartz. Such a device can also be used for duplexing bidirectional signals. Methods for mechanically tuning the devices to given laser wavelengths are described, as well as simplified constructions which can be used with polarized light sources such as lasers.

Birefringent optical wavelength multiplexer/demultiplexer

A precision molded elastomeric optical fiber holder, for holding an optical fiber of a first diameter, comprises a molded cylindrical piece of elastic material having an axial hole of a second diameter from one end of the piece to another end thereof. The hole is tapered to a third diameter near one only of the ends. The third diameter is greater than each of the first and second diameters. Prior to insertion of the fiber, the second diameter is smaller than the first diameter.

Optical fiber holders

A nondestructive optical test set-up for measurement of critical parameters of expanded beam connectors which does not require the insertion of fibers into the connector or contact to any critical surface. The method is independent of fiber preparation techniques, assembly procedure, and connector housing accuracy.

Optical test set-up for expanded beam connector

Polarization-insensitive optical switch and dual channel carrier multiplexer includes a polarization beam splitter for receiving an input collimated beam which has arbitrarily polarized components, splitting the beam into the two components. One of the components is rotated by a 1/2 wave plate so as to yield a polarized beam which is polarized in the same direction as the other beam. The two polarized beams are then applied to a polarization sensitive interferometric multimode fiber optic switch and modulator. The output of the interferometric multimode fiber optic switch and modulator contains two beams, both polarized in the same direction. One of the beams is rotated ninety degrees by a 1/2 wave plate, and the two mutually perpendicularly polarized beams are then recombined by a polarization beam splitter operated in reverse to yield an output beam containing mutually perpendicular components.

Polarization-insensitive optical switch and multiplexing apparatus

Interferometric multimode fiber optic switches and modulators include combinations of various components. Two electro-optical crystals have a dielectric beam splitting coating affixed to portions thereof. The coated portions of the two crystals are juxtaposed. Means are provided for varying indices of refraction of the two crystals with respect to each other. Light entering into the first crystal and traveling within the two crystals can be switched to selectively exit from one crystal or from the other by varying the index of refraction of one of the crystals with respect to that of the other. By interferometric principle of operation, the phase relation of light is transformed into spatial direction. The crystals can be selected from the group consisting of lithium niobate, lithium tantalate, and barium strontium niobate. The dielectric beam splitting coating can be formed of multiple layers of material such as zirconium oxide and silicon dioxide. The indices of refraction of the crystals are varied by applying electric fields of one polarity at opposite surfaces thereof. Light enters the various crystals, and is reflected, and is transmitted at various surfaces thereof so that, upon entering a particular area within the crystals, reinforcement or interference of light can occur.

Interferometric multimode fiber optic switch and modulator

Polarization-insensitive optical switch apparatus

A telecentric optical fiber connector, wherein light from an optical fiber is emitted from the connector lens in a comparatively large diameter parallel beam, includes two primary components: an integral optical quality plastic connector body having an annular planar reference surface substantially perpendicular to an optical axis. A convex lens surface is molded, recessed inward from the reference surface. The body is substantially cylindrical, with exterior means thereabout so that it can be engaged with a similar body. The opposite axial end of the body has a central cylindrical cavity therein which extends to a point which is one focal length from the lens surface. A fiber holder, which holds an optical fiber centrally within an axial hole, abuts an end of the fiber against the point one focal length from the lens surface, and can be engaged with index-matching material.

Optical fiber connectors

A centering device, for holding an optical fiber along an axis, includes three sections of fiber receiving means, and a receiving member. The receiving member has a cylindrical recess, concentric with the axis, for holding the sections in assembly. The sections are substantially identical, each having a uniform cross-sectional configuration at right angles along a major portion of its length forming a boundary of fixed perimeter. One portion of the boundary of one section contacts another section. Another portion of the boundary contacts a different section. A third portion contiguous to the first two portions is adapted to engage an optical fiber along its length. A fourth portion contiguous to the first two, but not to the third, engages the cylindrical wall defined by the concentric recess of the receiving member. The recess terminates with a planar wall perpendicular to the axis. It can have an axially oriented depression. The fourth portion of the boundary engages differing amounts of a cylindrical wall depending upon the shape of the fourth portion. The sections include elastomeric material of sufficient resilience for a passageway defined by the third portions of assembled sections to expandably receive an optical fiber dimensioned larger than the passageway. The passageway can have a substantially triangular cross-section for receiving a fiber having a substantially circular cross-section. It can flare outwardly from a position interior the fiber receiving means to respective ends thereof. Passageway flaring can have a triangular, a hexagonal, or a circular configuration. The device can have a fiber receiving means with a polygonal shaped external surface. The receiving member can be transparent. The fiber receiving means can be held within the recess of the member by a force fit. The radius of the three sections, when assembled but prior to insertion into the recess, is greater than the radius of the recess.

A one-piece molded elastomer splicer for permanent or temporary coupling of guided light between two optical fibers. Two cleaved fibers to be spliced are inserted into opposite ends of an elastic capillary tube somewhat smaller in diameter than the fibers, and pushed in until they meet in the center. Symmetrical elastic restoring forces automatically align the two fiber axes along the axis of the tube. When desired, the splicer can be transparent so that the resulting splice quality can be checked with a low-power microscope. Manual insertion of the fibers is possible with care, but a simple mechanical insertion jig is suggested. An optical fiber connector with built-in fiber-to-connector splice means connects two optical fibers with very low insertion losses even after many connect/disconnect cycles, with a simple and reliable means for installation in the field. The connector has a central mating interface, fabricated, aligned, polished, and anti-reflection coated at the factory, but with a built-in splicer for attaching to fibers in the field by the user.

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Boston, MA, United States of America

W John Carlsen