Northern Telecom Limited

Northern Electric Company Limited

Jack F Dalgleish

Helmut H Lukas

Jaroslav M Hvezda

David A Kahn

Grant K Pacey

Louis Donald Charron

Kahn: David A

An optical busbar, for optically interconnecting electronic and/or photonic equipment, comprises a rod of light-transmissive material, for example polycarbonate, having a longitudinal planar surface. Preferably the rod is of polygonal cross-sectional shape. Distributed along its length, opposite the planar surface, the rod has a plurality of inclined reflector surfaces for diverting light travelling along the rod so that it emerges laterally at intervals corresponding to the spacing of the reflector surfaces. When the rod is installed on a backplane of the equipment, with a plurality of circuit cards projecting perpendicularly from the backplane, optoelectrical devices on the circuit cards are arranged to be in register with the inclined reflector surfaces. Optical signals transmitted along the optical busbar will be distributed to the circuit cards. The optical conductor will, of course, function with the light travelling in the opposite direction, i.e. transmitted from the circuit card and reflected to travel along the length of the conductor.

Optical busbar

A mounting arrangement for mounting an optical conductor on a 'photonic' backplane provides for simple, accurate positioning during installation and easy access to, and removal of, the optical conductor when in service. The optical conductor constitutes a 'busbar' in that it has a series of reflector surfaces spaced along its length to permit distribution or aggregation of several light signals. In one embodiment, an individual support is provided at each reflector/circuit card location. Each support is a seating member which houses a lens to couple light between the optical conductor and the circuit card. In another, preferred, embodiment the optical conductor is housed in a channel in a guide rail mounted upon the backplane. Separate cover members are releasably mounted upon the guide rail adjacent each circuit card. Each cover member has an aperture and lens to couple light between the reflector and the circuit card. The aperture and lens may be in a boss which couples in spigot-and-socket fashion with a tubular lens-carrying coupled mounted on the circuit card.

Mounting optical busbars on backplanes

An optical fibre connector for connecting one or more pairs of single fibres in end-to-end relationship has an alignment member having two opposed and inclined datum surfaces, generally in the form of a Vee, and two tubular ferrules resting on the datum surfaces. The ferrules each have two datum positions extending along the ferrule and spaced circumferentially to cooperate with the datum surfaces. Each ferrule has a fibre receiving bore which is formed at a predetermined positional relationship to the datum positions. Rotational location is provided between ferrules and alignment member. The bore is formed by casting material in the ferrule using a mandrel, the ferrule and mandrel accurately positioned in an alignment tool which reproduces the datum surfaces of the alignment member. Build up of tolerances is avoided and slight variation in diameters of the ferrules, and lack of concentricity can be accommodated with accurate alignment of fibre ends still obtained. The invention can be used for a permanent connection, that is a splice, or for make, break and remake types of single or multiple connectors.

Optical fibre connector

A multiple connector for releasably connecting a plurality of pairs of optical fibres having two connector members, one having an axially moveable member therein with a plurality of axial holes, the other member having a plurality of aligning members extending axially. When assembled, an aligning member is aligned with an axial hole. The aligning member has a central bore portion a close fit on an uncoated fibre and tapered bores leading into the central bore portion. The axially moveable member is resiliently biased to project from a front face of the related connector member. On assembly the axially moveable member is pushed back into the connector member to expose one set of fibre ends which enter the aligning members. The other set of fibre ends are initially positioned in the aligning members. Preferably holding members are attached to the fibres and inserted from the rear of each connector member. This permits rear insertion of fibres. The holding members having locating members thereon for positioning the holding members, and the fibres axially in the connector members. Housings enclose the rear ends of the connector members.

Multiple connector for optical fibres

A tool for breaking an optical fibre comprises an elongate base member and an elongate top member pivotally connected at a rear end. An elongate cam member slides longitudinally in the base member, being actuated by pivotting of the top member. At the front end of the base member are a front pair of opposed gripping jaws and a further, rear, pair of gripping jaws are spaced from the front jaws. A bending member is positioned between the two pairs of jaws. Pivotting of the top member towards the base member actuates the cam member which in turn first closes the front jaws, then the rear jaws. The rear jaws then pivot backwards to tension the fibre and then the bending member moves up to cause the fibre to bend over an arcuate top surface. Finally a pivotally mounted scoring member in the top member is actuated to sweep a sharp edge across the fibre to initiate a crack, which propagates across the fibre.

Apparatus for breaking an optical fibre

A connector for optical fibres comprises two subassemblies, one subassembly comprising at least one tubular member the rear part of which fits on a coated fibre and the front part of which receives a connector element. The other subassembly includes at least one tubular connector element, the rear part of which fits on a coated fibre and the front part of which is a close fit on an uncoated fibre. On assembly of the two subassemblies, the connector element slides into the front part of the tubular member of the first subassembly. The ends of the uncoated fibres abut at about a mid position in the connector element. For a connector for multiple pairs of fibres, a plurality of tubular members are provided in one subassembly and a plurality of connector elements in the other assembly. Means can be provided for resiliently positioning one or the other or both of the tubular members and connector elements axially to permit axial movement on assembly to allow for manufacturing tolerances.

Optical fibre connectors

Two optical fibres are connected in end to end relationship by positioning the fibres in a tubular connecting member, the member having a preformed section which has a number of lobes formed in the tube, the radially inward extremities of the lobes defining an axial bore into which the uncoated ends of the fibres can slide. After positioning the fibre ends in the preformed section the plastic coating of each fibre is gripped by crimping the tubular member. For a splice both coated fibres are crimped into a single tubular member. For a releasable connector two tubular members are used, one incorporating the preformed section, and the two tubular members each crimped on to a fibre, the two members held together.

Method of connecting two optical fibres in end to end relationship

A tool for preforming a section of a tubular connector, the connector used for joining two optical fibres in end to end relationship. A plurality of forming members extend radially in a holder and spaced circumferentially around the tubular member support means supports a mandrel in the bore of the tubular member, coaxially thereof, and cams push the forming members radially inward to form a plurality of lobes in the section of the tubular member. The radially inward extremities of the lobes are pushed into contact with the mandrel to define a central bore for reception of the uncoated ends of the fibres. The forming members having a Vee formation with an inclined face at each end of the Vee formation.

Tool for preforming a section of a tubular connector

A connector comprising a tubular connecting member having a bore which fits over a coated fiber and having a section which is preformed by deforming the walls of the member inwards to define a smaller central bore which is a close sliding fit on an uncoated fiber. Two coated fibers are connected by the uncoated fibers ends being inserted into the preformed section, a fiber from each end, until in end to end relationship. For a splice, a single connecting member is used and after insertion of the fibers, the ends of the member are crimped on to the coated fiber. For a releasable connector, the preformed section is toward one end of the connecting member which is crimped on to one coated fiber. The other fiber is crimped into a further tubular member with the uncoated fiber extending from the end for insertion in the preformed section of the connecting member. The connecting member and the further tubular member are held in axial alignment by a housing.

Connectors for optical fibers

A clamp for a plastic coated optical fibre comprises a tubular portion which is a fairly close sliding fit on the coated fibre and an axially split portion having at least one resilient axially deformable finger. The dimension across the split section is slightly larger than across the other portion. An axially split sleeve is axially slidable on the clamp, and is freely slidable along the tubular portion on to the slit portion. Sliding of the sleeve on to the slit section deforms the finger into gripping contact with the fibre coating and also expands the sleeve. This provides a 'backing up' force and also accommodates variations in diameter of coated fibre. More than one finger can be provided, and serrations or other formations can be provided on the fingers.

Growing community of inventors

Ottawa, Canada

Jack F Dalgleish