Abstract: A method and apparatus for cross-connecting arbitrary fragments of an incoming virtual tributary synchronous payload envelope, or arbitrary fragments of any incoming transmission stream, at a cross-connect element within a communications network is provided without incurring a delay associated with aligning a frame phase of the first digital stream to any arbitrary frame timing reference. The arbitrary fragments are sized smaller than a complete virtual tributary, or equivalent thereof, of the first digital stream, and comprise one or more incoming payload bytes. The incoming payload bytes have incoming identifiers related to their incoming locations and outgoing identifiers related to their outgoing locations.

Abstract: A card cage for housing a plurality of circuit boards and passive optical fiber couplers contains a tray for storing express optical fibers or express optical fiber tubes not to be coupled within the card cage but rather expressly routed through a distribution point accommodating the card cage. The tray has a flexible hinge thereon and means for keeping the tray passively deflected away from the optical couplers for facilitating insertion and removal of optical fibers into and from the couplers. A card cage housing snap fits to a card cage base without requiring screws or other physically detachable elements. The housing also includes a plurality of flexible deflectable clips integrally molded as part of the card cage housing which normally keep the circuit cards or boards within the card cage housing but which are deflectable so as to allow the boards to be slideably inserted and removed from channels within the housing for guiding the boards.

Abstract: An optical fiber transmission network for transmitting voice, data, or video signals between telecommunication units includes optical couplers which bend an optical fiber at a location in close proximity to the fiber end so as to allow coupling with the fiber through its side rather than through the end of the fiber. This eliminates the need for cleaving and polishing the fiber end, and results in a craft friendly way of terminating an optical fiber end with a telecommunication unit.

Abstract: A cable connection is environmentally protected using an assembly which comprises a polymeric sleeve positioned over the coupling nut of the connector and a segment of the cable adjacent the connector, the polymeric sleeve being secured to said coupling nut so as to prevent motion between the sleeve and the nut and a layer of encapsulant positioned between at least a portion of the polymeric sleeve and the underlying cable, the encapsulant providing a circumferential environmental seal between the cable and the sleeve while permitting rotational motion between the cable and the sleeve. A further layer of encapsulant preferable extends from the coupling nut over the hardware mounting the connector receptacle into a bulkhead. This further layer of encapsulant is preferable contained in a cap to which a force is applied by a flange provided in the polymeric sleeve. The encapsulant is preferable a silicone gel.

Abstract: A protocol for fiber-optic communication systems, or other communication systems based on transmission of unipolar pulses having wide dynamic range provides for information to be transmitted in packets having a predictable time slot for each transmitter. The receiver for such protocol has a first relatively long RC time constant mode conditioned for reception of data packets whose time of arrival is well predictable and a second relatively short RC time constant mode conditioned for reception of asynchronous randomly received packets. In the relatively long RC time constant mode, each packet includes a preamble having a first clamp interval in which no pulse is transmitted, and a second clamp interval in which a continual pulse is transmitted. A transducer on the receiver translates the packets of pulses into differential electronic signals on first and second outputs.

Abstract: An optical fiber splice tube holder includes a plurality of torsion bars and cantilever bars which provide a resilient retaining force for an optical fiber splice container to be retained therein. The use of torsion bars helps distribute stress generated by a spring force of the fiber splice member holder about a large amount of material so as to achieve an efficient spring construction so that a plurality of splice holders can be accommodated in a reduced space on a fiber storage tray.

Abstract: A transimpedance front end is provided for an optical receiver which includes a photodetector coupled optically to an optical fiber for receiving optical signals over the fiber and connected electrically to the front end. The front end comprises a buffer amplifier connected to the photodetector, a first amplifier selectively connected to the buffer through a first switch and through a first, high value feedback resistor in order to define a first mode low optical signal level amplifier configuration, a second amplifier selectively connected to the buffer through a second switch and through a second, switched low value resistor to define a second mode high optical signal level amplifier configuration, and an optical level sensing and switching control circuit connected to the photodetector for sensing incoming optical signal level and for switching between the first and second amplifier configurations as a function thereof.

Abstract: A strained distributed optical fiber distribution network includes read and write optical fibers having taps attached thereto in series so as to strain portions of the fiber in excess of 0.60%, the strained portions being environmentally isolated by an enclosure which includes gel filled seals subject to a resilient load.

Abstract: A printed circuit board apparatus includes a handle which has an extension plate which extends into an optical switch so as to prevent communication between an optical emitter and optical receiver. To remove the printed circuit board apparatus from its associated rack housing, rotation of the handle is first required which moves the plate and which causes the detector to go HIGH and signal to a telecommunications system that the board is soon to be removed so that a graceful switch can be made from that board to a redundant copy thereof. The printed circuit board apparatus further includes a deflectable lever which contacts to ground the rack housing upon inserting the printed circuit board apparatus into its associated rack housing so as to provide electrostatic discharge protection.

Abstract: A coupler for a fiber optic light waveguide has phase space matching optics to increase coupling efficiency. The acceptance phase space of the fiber optic waveguide has two components for light in two orthogonal planes. One of the phase space plots has a straight spine and the other has a bent spine. The phase space matching optics include a graded index lens optically coupled to the phase of a light emitting diode, in the case of a write coupler, which alters the emitted light phase space at a reference plane of the emitted light to match, at the reference plane, the acceptance phase space component having the straight spine. Another lens takes the output light from the graded index lens and alters the phase space further to match the phase space component having the bent spine.

Abstract: A transmit control store is provided for assembling recurrent data packets of information for transmission over an optical fiber communications network from a host digital terminal to a variable number of optical network units, wherein each optical network unit serves a variable number of individual subscriber stations, and wherein each frame contains a programmed number of optical network unit packets wherein each packet has a byte length related to the number of subscriber stations served and bandwidth required thereby.

Abstract: An optical receiver includes a photodetecting device and a wide band video amplifier. The photodetecting device and the video amplifier are coupled by reactive elements which are selected to provide a highly linear and highly sensitive response over a frequency range of approximately 400-950 MHz. The crosstalk between two signals are ten parts per billion when the laser power is at 1 milliwatt and modulation is 25 percent per signal. The noise generated by the receiver is only equivalent to 6 billionth of an ampere. The receiver uses commerically available components.

Abstract: A self-correcting protective circuit for providing a reference voltage to a backplane bus wherein the circuit includes a primary transistor, current sensing resistor and diode connected between a supply voltage and the backplane. The combination of a current-limiting resistor and a control transistor is used to sense current flow to the board through the primary transistor and limit same when the backplane bus voltage fluctuates.

Abstract: A linear optical broadband signal generator includes primary and secondary optical modulators whose outputs are combined so as to minimize intermodulation distortion of a modulated optical signal. A constant amplitude optical signal is split differentially so as to create primary and secondary power levels, the primary and secondary power levels being inputted into the primary and secondary modulators. An electrical input to one of the modulators is differentially attenuated so as to reduce third order modulation products when modulated outputs of the modulators are combined. In addition, the total modulated optical output power is maximized by adjustment to one of the outputs of one of the modulators so that its phase is more in line with a phase of the output of the other modulator so as to maximize first order products of the combined output.

Abstract: A dispenser for dispensing an index matching coating material onto an end of an optical fiber to be terminated includes a reservoir formed by a floor and sidewalls with a small portion of the index matching coating material being disposed on a top surface of the floor. An interior perimeter shape of the sidewalls is registrable with an external perimeter shape of an optical fiber contact to which the optical fiber is secured which allows the index matching material to be conveniently disposed on an end of the optical fiber by simply inserting the optical fiber contact into the reservoir.

Abstract: A strained distributed optical fiber distribution network includes read and write optical fibers having taps attached thereto in series so as to strain portions of the fiber in excess of 0.60%, the strained portions being environmentally isolated by an enclosure which includes gel filled seals subject to a resilient load.

Abstract: An apparatus for protecting a substrate includes a collapsible reservoir filled with a three-dimensional elastic gel which is relatively soft and has an ultimate elongation of at least 200%. The apparatus is disposed in contact with a substrate having a recess therein to be environmentally protected, and a force is applied to the reservoir to at least partially collapse the reservoir forcing the gel from an open surface of the reservoir into the recess so as to substantially fill and encapsulate the recess.

Abstract: An output of a light source coupled to an optical fiber is controlled by an apparatus comprising a mode stripper for stripping a first part of the optical signal from the cladding of the optical fiber, means for bending the optical fiber and withdrawing a second part of the optical signal from a core of the fiber downstream from the stripper, means for detecting the second part of the optical signal, and feedback means for using the detected second signal part to control an output of the light source to better linearize an amount of power injected into the fiber.

Abstract: An optical fiber enclosure for a pedestal environment includes a pedestal which slideably supports a closure within the pedestal along a vertical direction so that during freeze-thaw envionrmental conditions when the pedestal is raised and lowered by expanding and contracting earth the closure does not impose undue stress on optical fiber cables connected thereto. Another enclosure suitable for buried applications also includes means for slideably extending an inner closure therefrom along a vertical direction to aid a craftsperson in accessing and working on the inner closure, the buried enclosure including means for allowing one or more loops of telecommunications cable to be stored therewithin for allowing the inner closure to be removed a substantial distance therefrom.

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.