Abstract: A laser diode protection circuit includes an input connected to receive the RF amplitude modulating signal. A second RF amplifier is connected to amplify the received RF amplitude modulating signal and to put out an amplified signal. A sensing element such as differential amplifier or Schmitt trigger is connected to put out a control signal when the amplified signal exceeds in amplitude a reference level. A switching element preferably includes a series PIN diode network having a PIN diode connected in parallel in reverse conduction order across the laser diode. The switching arrangement is responsive to the control signal and effectively swamps or diverts the forward conduction current away from the laser diode thereby causing it to become reverse biased.

Abstract: This invention provides an enclosure for a butt splice of optical fibre cables which includes organizer trays for storing the excess lengths of individual optical fibres. The enclosure and trays provide for access to the individual fibres for splicing or repair.

Abstract: A splice case for encapsulating a substrate includes first and second containers each of which contain a gel having a cone penetration between 100 and 350 (10.sup.-1 mm) and an ultimate elongation of at least 200%, the gel in each container having an exposed surface, one exposed surface having a cross-sectional area larger than the cross-sectional area of the other exposed surface, the first and second containers being adapted for telescopic engagement.

Abstract: Forming an optical fiber so as to have a relatively constant bend loss characteristic includes apparatus for continuously bending the optical fiber downstream from a preform from which it is drawn and continuously detecting light withdrawn from the fiber at the bend so created to determine the fiber bend loss characteristic, the fiber bend loss characteristic being maintained constant by using feedback control to vary a drawing speed of the fiber and hence a diameter of a core of the fiber.

Abstract: An optical fiber read or write tap includes a substrate having a substantially flat upper surface on which two separated grooves are formed, a light element being disposed in the second groove so as to be capable of coupling light with a bent portion of an optical fiber disposed in the first groove.

Abstract: An optical fiber tap for connecting polymer optical fibers is achieved by heating an end section of the fibers to be connected and deforming the end sections into a non-circular cross-sectional shape so as to form a throughput cross-sectional area and a add/drop throughput area, the optical fiber ends being thereafter aligned so as to allow for efficient signal extraction and injection.

Abstract: A fiber optic connector which includes a connector body having at least one socket cavity therein and a socket contact inserted into the socket contact cavity. The socket contact has a retention area and a cable termination area at one end and a retractable contact portion at the other end. The connector further includes means on the retractable contact portion for limiting axial movement of the contact portion so that when the contact portion is unretracted, a tip of the contact portion is substantially flush with a surface of the connector body.

Abstract: An optical fiber distribution network includes non-destructive read taps disposed in series which create extremely small attenuations of an optical signal being tapped, and which increase the bandwidth of an optical fiber being tapped. The network further includes non-destructive write taps disposed in another series which each inject an optical signal into a second optical fiber while inducing minimal attenuation of a preexisting optical signal in the second fiber.

Abstract: An optical fiber coupler for injecting light into, and withdrawing light from, an optical fiber utilizes a deformable material (8) and a clamping member (4) which clamp a buffered optical fiber (6) therebetween. Both the clamping member and deformable material are curved causing the optical fiber to be bent when so clamped resulting in light coupling between an optical fiber core and the deformable material through the fiber buffer. The deformable material is substantially transparent and has an index of refraction substantially equal to that of an outer surface of the optical fiber. A light element has a surface embedded within the deformable material, and the deformable material and coupler are specifically formed so as to reduce microbend stresses induced in the fiber when so clamped so as to increase coupling efficiency.

Abstract: A tap for withdrawing light from an intermediate portion of an optical fiber core by passing light through a side of the optical fiber comprises an optical coupler in contact with an outside surface of an optical fiber which is bent and disposed in a plane. A light reflector extending transverse to the plane deflects the withdrawn light towards the end surface of a light element disposed completely outside the plane. A similar arrangement may be used to inject light to an intermediate portion of an optical fiber. The tap may be used as a read tap to withdraw light, or as a write tap to inject light in optical fiber networks.

Abstract: An optical fiber tap which is especially useful as a node in a ring topology data processing system. The tap, which does not interrupt the physical continuity of the fiber, has an open position and a closed position. In the open position, a signal passing down the optical fiber passes through the tap without alteration. In the closed position, a signal passing down the optical fiber is extracted through a first bend which is put into the fiber by the tap; the extracted signal, or an electrical counterpart thereof, is processed and a counterpart of the extracted signal, or a new signal obtained by operating on the extracted signal, e.g. in a data processor, is injected into the fiber through a second bend which is put into the fiber by the tap.

Abstract: An optical fiber cable construction includes a first fiber marker which allows one initially to determine a linear length of the optical fiber between first and second points, and a second marker which allows one to determine a linear length of the fiber optical cable between the first and second points, thus ensuring that the length of the fiber initially exceeds the length of the cable during initial installation so as to minimize the chances of excessive temperature induced stress being imposed on the optical fiber during its useful life.

Abstract: A D-shaped fiber which has an evanescent-field which is easily tapable has a low attenuation since a buffer material disposed on a cladding planar side of the waveguide has an index of refraction lower than the cladding so as to effectively increase a radius of the cladding in the vicinity of its planar side so as to minimize signal loss into the fiber buffer.

Abstract: A mode filter for reducing a dynamic range of a write optical fiber bus which utilizes taps which initially inject optical signals into an optical fiber which have intensities skewed towards higher order modes rather than lower order modes as compared to equilibrium for the fiber functions to preferentially attenuate outermost modes rather than lowermost modes in the fiber so as to reduce a required dynamic range for an optical receiver.

Abstract: A method of forming an optical fiber elbow includes bending a straight optical fiber while subjecting the fiber to an elevated temperature for an amount of time sufficient to anneal strain out of the bent section of the optical fiber such that upon cooling the optical fiber maintains a bent attitude with little or no strain in the bend.

Abstract: A distribution optical fiber network includes a light source having a mode volume less than a distribution optical fiber, the light source being connected to the fiber so as to minimize the number and order of modes initially supported by the fiber by aligning an optical center of the light source with a geometric center of the fiber.

Abstract: Methods, apparatus and articles for systems comprising optical fibers, in particular for feeding an optical signal into an optical fiber through the buffer thereof and for withdrawing an optical signal from an optical fiber through the buffer thereof. Preferably this is achieved with the aid of an optical coupling means which contacts and conforms to the surface of the buffer at a bent portion of the fiber. The coupling means can for example be a resiliently deformable material such as a polysiloxane. In a preferred aspect, the invention provides an apparatus and method for axially aligning, and preferably joining, the ends of optical fibers. The apparatus comprises means for holding two fibers so that the fiber ends are approximately abutting and axially aligned, adjacent means for passing an optical signal into one of the fibers through the buffer thereof, and adjacent means for withdrawing that signal from the other fiber through the buffer thereof.

Abstract: An optical fiber contact for terminating an optical fiber includes a solid multi-part thermoset mixture in a cavity in a front portion of the contact, an optical fiber being terminated by heating the thermoset so as to cause it to soften and liquify and subsequently inserting an optical fiber through the contact. The thermoset when liquified chemically reacts so as to form an epoxy adhesive which secures the optical fiber within the contact and keeps the optical fiber in place even when subjected to extremely wide temperature variations.

Abstract: An assembly for interconnecting a plurality of first contacts disposed in a ribbon array with a plurality of second contacts, also disposed in a ribbon array, includes a plurality of cylindrical radial springs which are split longitudinally along an axial direction of the contacts, each radial spring providing three common lines of contact with the mating first and second contacts so as to precisely align front ends of mating the first and second contacts. The assembly further includes dynamic seals on opposite ends of an alignment insert which contains the cylindrical, radial springs, the dynamic seals preventing foreign matter from entering an interface between front ends of the mating first and second contacts, and also functioning to dampen shock- and vibration-induced displacements of the mating first and second contacts.

Abstract: A method of aligning an optical signal source and a waveguide which comprises; directing the signal into the waveguide, monitoring the intensity of the signal backscattered along the waveguide, and altering the relative positions of source and waveguide in response to said intensity.