Abstract: A back light unit includes a plurality of light emitting diodes positioned on a substrate and a plurality of flat lenses. A respective one of the plurality of flat lens are positioned a distance above a respective one of the plurality of light emitting diodes. Each of the plurality of flat lenses includes a plurality of annular segments having a common center. Each of the plurality of annular segments includes a prism shape microstructure having a first facet configured to refract the light in a desired direction and a second facet oriented in a plane that is parallel to a plane of an emitting surface of respective ones of the plurality of light emitting diode.

Abstract: A network element comprises a power interface to receive power from a power communication medium; a service interface to provide a telecommunication service over a service communication medium; management interface to receive management data over one of the service communication medium and the power communication medium via at least one primitive; and a control module to monitor the at least one primitive and to control operation of the network element based on the at least one monitored primitive.

Abstract: A method of controlling power in a network element includes powering the network element by receiving power from a power communication medium and providing a telecommunication service over a service communication medium. The method further includes monitoring a primitive related to the powering of the network element and controlling the powering of the network element based on the primitive.

Abstract: A integrated access device in a communication network. The integrated access device in one embodiment includes a network port, a plurality of telephony ports, a data port and communication circuit. The network port is adapted to provide dynamic time division multiplex (TDM) interface to a communication network. The plurality of telephony ports are adapted to provide telephony service to subscriber premises equipment. The data port is adapted to provide digital subscriber line (DSL) service to subscriber premises equipment. The communication circuit is coupled to the network port, the plurality of telephony ports and the data port. Moreover, the communication circuit is adapted to carry voice and data signals between the network port and the plurality of telephony ports and the data port. In addition, the integrated access device is line powered over the network port.

Abstract: A method of controlling power in a network element includes powering the network element by receiving power from a power communication medium and providing a telecommunication service over a service communication medium. The method further includes monitoring a primitive related to the powering of the network element and controlling the powering of the network element based on the primitive.

Abstract: An optical transmission system exploits the reduced signal-to-noise (SNR) requirements for low-bit rate channels to devise a new wavelength channel allocation scheme which increases the number of channels that a WDM system can support. Wavelengths of low-bit rate channels are assigned outside a flat-gain window (i.e., flat-passband region) of the system. The channel allocation scheme uses the high-bit rate channels located in the flat-passband region of wavelengths and the lower-bit rate channels located outside this passband region with progressively lower-bit rate channels located farther outside this passband region. Low-bit rate channels are also assigned to region(s) of the passband where the non-linear threshold power level of the system may be exceeded.

Abstract: An optical transmission system exploits the reduced signal-to-noise (SNR) requirements for low-bit rate channels to devise a new wavelength channel allocation scheme which increases the number of channels that a WDM system can support. Wavelengths of low-bit rate channels are assigned outside a flat-gain window (i.e., flat-passband region) of the system. The channel allocation scheme uses the high-bit rate channels located in the flat-passband region of wavelengths and the lower-bit rate channels located outside this passband region with progressively lower-bit rate channels located farther outside this passband region. Low-bit rate channels are also assigned to region(s) of the passband where the non-linear threshold power level of the system may be exceeded.

Abstract: An optical transmission system exploits the reduced signal-to-noise (SNR) requirements for low-bit rate channels to devise a new wavelength channel allocation scheme which increases the number of channels that a WDM system can support. Wavelengths of low-bit rate channels are assigned outside a flat-gain window (i.e., flat-passband region) of the system. The channel allocation scheme uses the high-bit rate channels located in the flat-passband region of wavelengths and the lower-bit rate channels located outside this passband region with progressively lower-bit rate channels located farther outside this passband region. Low-bit rate channels are also assigned to region(s) of the passband where the non-linear threshold power level of the system may be exceeded.

Abstract: A integrated access device in a communication network. The integrated access device in one embodiment includes a network port, a plurality of telephony ports, a data port and communication circuit. The network port is adapted to provide dynamic time division multiplex (TDM) interface to a communication network. The plurality of telephony ports are adapted to provide telephony service to subscriber premises equipment. The data port is adapted to provide digital subscriber line (DSL) service to subscriber premises equipment. The communication circuit is coupled to the network port, the plurality of telephony ports and the data port. Moreover, the communication circuit is adapted to carry voice and data signals between the network port and the plurality of telephony ports and the data port. In addition, the integrated access device is line powered over the network port.

Abstract: Applicants have discovered that glass optical waveguides subject to hydrogen-induced loss increases can be passivated by treating the glass with deuterium. The deuterium-treated glass not only exhibits a lower rate of loss increase when later exposed to environments containing H2, but also retains high transmission of light in the 1.55 and 1.31 micrometer wavelength regions immediately after the deuterium heat treatment. The method applies to Er-doped fiber, transmission fiber and planar waveguides. Under some circumstances, hydrogen can be substituted for deuterium.

Abstract: In accordance with the invention, an optical communication system is provided with one or more automatic dispersion compensation modules. Each module has an adjustable dispersion element, a data integrity monitor and a feedback network whereby the monitor adjusts the dispersion element to optimize system performance. In a preferred embodiment the dispersion compensating modules comprise chirped fiber Bragg gratings in which the chirp is induced in the grating by passing a current along distributed thin film heaters deposited along the length of the fiber. The magnitude of the applied current determines the dispersion of the grating. A data integrity monitor is configured to sense the integrity of transmitted data and to provide electrical feedback for controlling the current applied to the grating.

Abstract: A high speed optical communication system (≧10 Gbit/s) is compensated for temperature variation by providing it with one or more automatic dispersion compensation modules. Each module has an adjustable dispersion element, a data integrity monitor and a feedback network whereby the monitor adjusts the dispersion element to compensate for temperature variation. In a preferred embodiment the dispersion compensating modules comprise chirped fiber Bragg gratings in which the chirp is induced in the grating by passing a current along distributed thin film heaters deposited along the length of the fiber. The magnitude of the applied current determines the dispersion of the grating. A data integrity monitor is configured to sense the integrity of transmitted data and to provide electrical feedback for controlling the current applied to the grating.

Abstract: In accordance with the invention an optical fiber communication system comprising a source of optical signals and an optical fiber transmission line is provided with one or more multiple-order distributed Raman effect amplifiers downstream of the source for amplifying the transmitted signals. As compared with a communication system using conventional first order Raman amplifiers, multiple-order amplifier systems can have reduced noise, longer fiber span lengths and reduced nonlinearities. In a preferred embodiment the system uses signal wavelengths in the range 1530-1570 nm, first order Raman pumping at 1430-1475 nm and second order pumping at about 1345 nm. Advantageously, the second order pump light is copropagating with the signal light and the first order pump is counterpropagating with the signal.

Abstract: The deposition rate of MCVD processes is enhanced by applying at least a first and a second independently controlled heat source to a plurality of reactants which are used to form deposited particulate matter. The first heat source is adjusted so as to provide at least a specified rate of reaction for the reactants, and the second source is adjusted so as to provide at least a specified deposition rate for the particulate matter.

Abstract: A large optical preform 303 is made by a modified chemical vapor deposition (MCVD) process by depositing successive layers of core and cladding materials onto the inside surface of a rotating glass tube 33 having a hydroxyl ion (OH.sup.-) level that is less than 0.5 parts per million (ppm) by weight. The tube is then collapsed inwardly to form a core rod 301 in which the deposited core material 31 has a diameter that is greater than about 5 millimeters and the deposited cladding material 32 has an outside diameter that is less than about 15 millimeters. A machine-vision system 140, 150, 160 monitors and controls the diameter of the glass tube by regulating the pressure within the tube. Moreover, the machine-vision system monitors and controls the straightness of the tube by varying its rotational speed according to angular position. After the core rod 301 is formed, it is plasma etched to remove contaminants, and then overclad with two glass jackets 34, 35 having a hydroxyl ion (OH.sup.

Abstract: We have found that the conversion efficiency of a Er/Yb-doped cladding pumped fiber amplifier increases with increasing signal input power. Thus, preamplification of the input signal by means of an Er-doped fiber amplifier can result in increased conversion efficiency of the cladding pumped power amplifier. Such increased efficiency is desirable, lessening heat removal problems and/or facilitating increased reliability.

Abstract: Magnets are used to control the amount of coupling loss between fibers. The fiber ends are attached to magnets and by controllably magnetizing the magnets, the fibers can be pulled apart or brought closer together to vary the amount of coupling loss. Preferably at least one of the magnets is latchable. The advantage of the latchable version is that a predetermined amount of loss can be latchably set by magnetizing the magnets to a particular level and afterwards no additional power is required to maintain the amount of attenuation. This is advantageous compared to other approaches in which power is required continuously to maintain a particular loss level.

Abstract: The disclosed optical fiber communication system comprises a remotely pumped erbium-doped fiber amplifier (EDFA). The pump radiation is de-tuned with respect to wavelength, the wavelength being selected longer than both the optimal wavelengths for pumping the EDFA and for producing Raman gain in the transmission fiber, respectively. Such de-tuning results in improved over-all system performance through reduced multi-path interference. Exemplarily, the pump radiation has wavelength in the range 1490-1510 nm.

Abstract: In an optically amplified multi-wavelength optical fiber communication system, deleterious effects due to channel addition/removal can be reduced or avoided if the optical amplifiers are "overpumped", that is to say, the system is selected such that at least 70%, preferably 90% or more, of the pump power that is introduced into the amplifier fiber is unabsorbed in the amplifier fiber.

Abstract: In one embodiment, an optical transmitter, which has a modulator disposed between an pair of optical amplifiers, exhibits reduced carrier-to-noise ratio and relatively high powers. In another embodiment, an optical amplifier is disposed between the laser carrier source and the modulator, but the post-modulator amplifier is omitted. Application of the transmitters to analog systems (e.g., CATV) and digital systems is described.