Abstract: A family of ultra-dense wavelength division multiplexing/demultiplexing devices are disclosed. In the case of an ultra-dense wavelength division multiplexing device, a wavelength division multiplexing device is used for combining at least one plurality of monochromatic optical beams into a corresponding at least one single, multiplexed, polychromatic optical beam, wherein the wavelength division multiplexing device has an input element and an output element. A plurality of optical input devices is disposed proximate the input element, wherein each of the plurality of optical input devices communicates a plurality of monochromatic optical beams to the wavelength division multiplexing device for combining the plurality of monochromatic optical beams into a single, multiplexed, polychromatic optical beam.

Abstract: A wavelength division multiplexer (WDM) including a support structure that is coupled to at least one optical component. A diffraction grating is optically coupled to at least one optical component coupled to the at least one optical component. A frame is coupled to the diffraction grating. Pins may be coupled between the support structure and the frame to substantially thermally isolate the support structure from the frame. The pins may be substantially geometrically equally spaced and have approximately the same exposed length extending from the lens barrel. The pins may have the same coefficient of thermal expansion as the support structure.

Abstract: A technique for detecting the status of wavelength division multiplexed optical signals is disclosed. In a preferred embodiment, the technique is realized by first splitting an original, multiplexed, polychromatic optical beam into at least two representative, multiplexed, polychromatic optical beams. Next, a first of the at least two representative, multiplexed, polychromatic optical beams is separated according to wavelength into a plurality of optical signal channels, wherein each of the plurality of optical signal channels are for communicating a respective, representative optical signal via a respective, representative, discrete, monochromatic optical beam. Finally, the presence or absence of a representative optical signal is detected on each of the plurality of optical signal channels.

Abstract: Inflatable head protector units are located at a unitized passenger compartment in the vicinity of roof frame sections with an energy-absorbent molded part being provided as a head impact protector at the level of each inflatable head protector unit. The molded part is designed as a launch ramp to guide an expanding airbag of the head protector unit into the desired protective position and located so that the molded part remains positioned at least largely dimensionally stably during the expansion of the airbag.

Abstract: An improved diffraction grating for wavelength division multiplexing/demultiplexing devices is disclosed. The improved diffraction grating has a glass substrate, a polymer grating layer located adjacent to the glass substrate, and a metal coating layer located adjacent to the polymer grating layer. The improvement comprises a polymer coating layer located adjacent to the metal coating layer, and a glass cover located adjacent to the polymer coating layer, wherein the polymer coating layer and the glass cover compensate for thermal characteristics associated with the polymer grating layer and the glass substrate, respectively.

Abstract: A technique for processing dense wavelength division multiplexed optical signals in a network node is disclosed. In one embodiment, the technique is realized as an optical power managed network node comprising a dense wavelength division multiplexing device for combining a plurality of narrowband optical signals into a multiplexed polychromatic optical signal. The optical power managed network node also comprises a wavelength-selective optical power detector for detecting the power of each of the plurality of narrowband optical signals combined into the multiplexed polychromatic optical signal. The optical power managed network node further comprises a plurality of attenuators for attenuating the power of at least one of the plurality of narrowband optical signals based upon the detected power of each of the plurality of narrowband optical signals.

Abstract: A technique for processing dense wavelength division multiplexed optical signals in a network node is disclosed. In one embodiment, the technique is realized as an optical power managed network node comprising a dense wavelength division multiplexing device for combining a plurality of narrowband optical signals into a multiplexed polychromatic optical signal. The optical power managed network node also comprises a wavelength-selective optical power detector for detecting the power of each of the plurality of narrowband optical signals combined into the multiplexed polychromatic optical signal. The optical power managed network node further comprises a plurality of attenuators for attenuating the power of at least one of the plurality of narrowband optical signals based upon the detected power of each of the plurality of narrowband optical signals.

Abstract: A family of ultra-dense wavelength division multiplexing/demultiplexing devices are disclosed. In the case of an ultra-dense wavelength division multiplexing device, a wavelength division multiplexing device is used for combining at least one plurality of monochromatic optical beams into a corresponding at least one single, multiplexed, polychromatic optical beam, wherein the wavelength division multiplexing device has an input element and an output element. A plurality of optical input devices is disposed proximate the input element, wherein each of the plurality of optical input devices communicates a plurality of monochromatic optical beams to the wavelength division multiplexing device for combining the plurality of monochromatic optical beams into a single, multiplexed, polychromatic optical beam.

Abstract: A method and device are disclosed for monitoring communication activity within an optical communications network. The device includes a pair of optical components for tapping optical signals transported across a fiber optic line in the optical communications network. At least one optical performance monitor (OPM) receives tapped signals from the pair of optical components. An optical switch, controlled by the OPM, selectively provides to the at least one OPM tapped signals corresponding to optical signals traveling on the fiber optic line in a first direction. The OPM measures the various signal characteristics of the tapped signals when the optical switch is opened and closed, and determines the direction of travel of optical signals on the fiber optic line based upon the measured signal characteristics.

Abstract: A route finder means and method for finding routes to satisfy a plurality of connection requests in a communications network comprising a plurality of nodes connected by a plurality of links. A cost is assigned to each network link. Arrays of eight shortest paths of links between each pair of nodes in the network are created. Bit strings comprising for example a 3 bit binary number for each point-to-point connection request are generated. Each 3 bit number is an index to one element of the shortest path array for each connection request's source and destination nodes. The bit strings are assembled into population members which are manipulated by genetic algorithms. The fitness of the population members is evaluated by calculating the cost of traversing the routes represented by the bit strings. The route finder means and method has an ability to split traffic over multiple routes, and to handle different traffic types, eg different bit rate traffic types.

Abstract: A route finder for point to multi-point connection requests in a communications network comprising a plurality of nodes connected by a plurality of links. A cost is assigned to each network link. For each connection request a set of all network nodes not included in its source node or its plurality of destination nodes are selected. An array of bits is created with an array element corresponding to a selected node element having a value of 1 if the node is steiner vertex for a steiner tree of nodes not selected, otherwise the array element has a value of 0. Each array is treated as a bit string and considered as population members which are manipulated by genetic algorithms. The fitness of the population members is evaluated by calculating the cost of traversing the routes represented by the bit strings. The method is capable of routing a plurality of multi-point connection requests, and selecting an overall optimum solution.

Abstract: A method of managing a communications network is described which makes use of information about the current state of the network and in addition, information about past and/or future states of the network. Information about the current state of the network is stored in a management information base (MIB) and the information about the past/future states is either stored in this MIB, or separate past/future MIBs are created. The information about the past/future states is stored in a way such that it can be operated on in the same way as the information about the current state of the network. By storing the information in this way management of the network is improved. For example, future states of the network can be tested before being implemented. Also, information about past states can be used to predict future states. Fault management, configuration management, accounting management and performance management can all be improved by using the information about past/future states.

Abstract: A method is provided for forming a molten oxide ceramic electrode for a plasma arc ignited between first and second electrodes within a plasma arc chamber, wherein the conductivity the oxide ceramic is a function of temperature alone. Following ignition of the plasma arc, a mixture is formed of a small quantity of molten oxide ceramic and a sufficiently high concentration of a volatile contaminant to render the mixture electrically conductive. The plasma arc is then transferred from one of the electrodes to the mixture. The temperature of the mixture is raised sufficiently to render the oxide ceramic electrically conductive. Finally, the volatile contaminant is progressively removed from the mixture so as to leave an electrode composed of substantially pure molten oxide ceramic.

Abstract: A method is provided for forming a molten oxide ceramic electrode for a plasma arc ignited between first and second electrodes within a plasma arc chamber, wherein the conductivity the oxide ceramic is a function of temperature alone. Following ignition of the plasma arc, a mixture is formed of a small quantity of molten oxide ceramic and a sufficiently high concentration of a volatile contaminant to render the mixture electrically conductive. The plasma arc is then transferred from one of the electrodes to the mixture. The temperature of the mixture is raised sufficiently to render the oxide ceramic electrically conductive. Finally, the volatile contaminant is progressively removed from the mixture so as to leave an electrode composed of substantially pure molten oxide ceramic.

Abstract: An improved focus and tracking error detection circuit for an optical disk servo system. The circuit calculates the logarithm of the signal from each of at least a pair of photodetectors. The difference between two logarithmic signals is then determined to give an error signal. The invention takes advantage of the property of logarithms that the difference between two logarithmic signals is equivalent to the logarithm of the ratio of the two signals. Accordingly, the error signal is a ratio, rather than an absolute difference signal, and is thus insensitive to variations which affect both signals. In addition, the logarithmic circuits inherently minimize variations which affect the photodetectors unequally by performing an AGC-type function. The error signal is inhibited during a write pulse to the laser to prevent saturation of the amplifiers. An automatic, periodic offset adjustment is provided by turning off the laser and varying an offset voltage until the error signal is zero.

Abstract: A system for storing and retrieving encoded data on an optical recording medium using pit edge detection is disclosed. The pit extension characteristics of a given medium are determined by first using laser beam test write pulses to form one or more pits on the medium and then detecting the time durational difference between the pulse width of the test write pulses and the duration of the leading edge transitions to trailing edge transitions of the corresponding pits formed on said medium. This difference value may be stored in a certification sector of the medium. Subsequent write pulses are modified in duration in an amount equal to this detected durational difference. For forming a pit that is longer than a predetermined minimum length, the corresponding write pulse is made non-continuous in order to minimize cumulative pit extension.

Abstract: A spear head access mechanism in a liquid development system wherein a machine mounted manifold, bearing a flow-through spear head connects the developer delivery system to a storage bottle. The bottle has a self sealing closure through which the spear head is forced and is encircled in an air tight manner when the bottle is pushed into operational position. A suction tube within the bottle is entered by the spear head. Upon removal of the bottle from the machine the self sealing closure forms a liquid tight seal preventing spillage of any remaining contents.

Abstract: An electrographic recorder of modular construction within which are a liquid development system and various electrical elements. Electromechanical connections between the electrical components and a housed power supply are made via a power distribution card lying upon the floor of the machine. To prevent electrical faults caused by liquid developer contamination, compartments are formed within the machine housing for isolating all liquid developer storage and usage locations from the electrical components. The compartments are configured to allow cooling air to be drawn into and through the housing, within the electrical component zone.

Abstract: An electrographic recorder including a unitary writing, developing and driving assembly comprising a precisely machined frame member to which is secured in accurate alignment a writing head positioning block, a developing fountain and a drive motor and roller. The assembly is attached to a support chassis for storing and feeding a supply of record bearing material so that the mounted components are properly positioned when acting on the record bearing material.