Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: Link robustness, chromatic dispersion and polarization mode dispersion (PMD) immunity can be improved in fiber optical system by using a method for receiving an optical double sideband signal over an optical fiber system, comprising the steps of splitting the received optical double sideband signal into an upper sideband signal and a lower sideband signal, photodetecting the upper sideband and the lower sideband, equalizing the photodetected upper sideband signal and the lower sideband signal, and combining the equalized upper sideband signal with the equalized lower sideband signal. While PMD compensation is envisioned as a major application, one may also use the method and system for chromatic dispersion compensation or dispersion slope compensation in high bit rate systems, i.e. using dispersion compensation fiber (DCF) for coarse compensation and diversity receiver with electrical equalizer for fine tuning.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: A system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is described. For example, the method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons comprises the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in the data signal, transmitting the encoded data signal over the fiber optical communications link, receiving the encoded data signal and decoding the encoded data signal.

Abstract: Link robustness, chromatic dispersion and polarization mode dispersion (PMD) immunity can be improved in fiber optical system by using a method for receiving an optical double sideband signal over an optical fiber system, comprising the steps of splitting the received optical double sideband signal into an upper sideband signal and a lower sideband signal, photodetecting the upper sideband and the lower sideband, equalizing the photodetected upper sideband signal and the lower sideband signal, and combining the equalized upper sideband signal with the equalized lower sideband signal. While PMD compensation is envisioned as a major application, one may also use the method and system for chromatic dispersion compesation or dispersion slope compensation in high bit rate systems, i.e. using dispersion compensation fiber (DCF) for coarse compensation and diversity receiver with electrical equalizer for fine tuning.

Abstract: A system and method is provided for minimizing power fluctuations and crosstalk in a wavelength division multiplexed optical (WDM) network employing dynamic add/drop techniques by utilizing amplifiers operating in a nearly linear region. Conventionally, erbium-doped fiber amplifiers (EDFAs) are operated in saturation for providing signal amplification in a WDM network. Instead of using saturated EDFAs, the present invention includes optical amplifiers operated in a linear or nearly linear regime for providing signal amplification in a dynamic add/drop or bursty data WDM network. By operating optical amplifiers in a linear or nearly linear regime, power fluctuations, transients and crosstalk caused by adding/dropping or switching channels in the WDM network are minimized. Raman amplifiers, EDFAs, or semiconductor optical amplifiers (SOAs) can all be operated in a linear or nearly linear range to provide linear amplification in such a dynamic add/drop or bursty data WDM network.

Abstract: A monitoring apparatus and method are provided for a communication system in which a central office communicates to at least one end unit using intermediate remote nodes. The remote node receives signals from both the central office and the end units. Each remote node can be equipped with apparatus for monitoring the integrity of paths of the communication system. The monitoring apparatus can include a mixing device that mixes received signals to produce combined signals. The received signals generally include a pilot signal sent from the central office and a data signal sent from the at least one end unit. The state of the communication system is analyzed based on the combined signals. If the combined signals includes only the data signal from the end unit, the path through which the pilot signal was sent is inoperative. If the combined signals includes only the pilot signal, the transmission path from the end unit over which the data signal is sent is inoperative.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: A method and system for generating and transmitting optical signals with only one sideband. Single-sideband optical signal transmission reduces the signal impairment effects associated with dispersion. Such transmission also increases the spectral efficiency of optical transmission systems. Single-sideband modulation also makes possible electrical compensation for optical link dispersion during transmission. Single-sideband modulation is generated using the modulating data signal and its Hilbert transform, which is approximated by a tapped-delay time filter. Line coding is used to remove the low-frequency content in the modulating data signal, avoiding the inefficiencies of tapped-delay-line filter approximated Hilbert transformers at low frequencies. Line coding can also help optical single side band signal generation and transmission using a simple optical filter instead of Hilbert transformers.

Abstract: A communication system between head-ends and end-users is provided which expands bandwidth and reliability. A concentrator receives communication signals from a head-end and forwards the received communication signals to one or more fiber nodes and/or one or more mini-fiber nodes. The concentrator demultiplexes/splits received signals for the mini-fiber nodes and the fiber nodes and forwards demultiplexed/split signals respectively. The mini-fiber nodes may combine signals received from the head-end with loop-back signals used for local medium access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and/or fiber node and transmitted to the concentrator. The concentrator multiplexes/couples the mini-fiber node and the fiber node upstream signals and forwards multiplexed/coupled signals to the head-end.

Abstract: An optical transmission system and method uses large-bandwidth optical signals that rapidly disperse in a transmission medium, such as an optical fiber, to reduce the effects of non-linearities in the transmission medium on the optical signal. The frequency bandwidth of the optical signals can be widened by chirping the optical signals, although other methods are possible. Optical signals in adjacent channels, such as in wavelength division multiplexing, can overlap to some extent without significant effect on the transmitted signal quality. Optical filtering at the receiver can extract partially overlapping signals as well as compensate for residual dispersion and/or dispersion slope in the transmission system.

Abstract: A communication network uses intermediate nodes to resolve local traffic contention. Intermediate nodes receive upstream signals from end users, derive traffic information signals from the upstream signals, and transmit the traffic information signals to end users. By listening to the traffic information signals from the intermediate node, the end users know whether the upstream transmission channels are idle or busy, or whether a collision has occurred. The intermediate nodes derive and transmit the traffic information signals with or without the assistance of the central office or head end.

Abstract: A system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is decribed. The method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons comprises the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in said data signal, transmitting said encoded data signal over said fiber optical communications link, receiving said encoded data signal and decoding said encoded data signal.

Abstract: A system and method is provided for minimizing power fluctuations and crosstalk in a wavelength division multiplexed optical (WDM) network employing dynamic add/drop techniques by utilizing amplifiers operating in a nearly linear region. Conventionally, erbium-doped fiber amplifiers (EDFAs) are operated in saturation for providing signal amplification in a WDM network. Instead of using saturated EDFAs, the present invention includes optical amplifiers operated in a linear or nearly linear regime for providing signal amplification in a dynamic add/drop or bursty data WDM network. By operating optical amplifiers in a linear or nearly linear regime, power fluctuations, transients and crosstalk caused by adding/dropping or switching channels in the WDM network are minimized. Raman amplifiers, EDFAs, or semiconductor optical amplifiers (SOAs) can all be operated in a linear or nearly linear range to provide linear amplification in such a dynamic add/drop or bursty data WDM network.

Abstract: A bi-directional optical transmission system provides communications between at least two locations over a single optical fiber. The transmitters at the respective locations are defined to have different optical spectra characteristics to avoid production of optical beat interference.

Abstract: A monitoring apparatus and method are provided for a communication system in which a central office communicates to at least one end unit using intermediate remote nodes. The remote node receives signals from both the central office and the end units. Each remote node can be equipped with apparatus for monitoring the integrity of paths of the communication system. The monitoring apparatus can include a mixing device that mixes received signals to produce combined signals. The received signals generally include a pilot signal sent from the central office and a data signal sent from the at least one end unit. The state of the communication system is analyzed based on the combined signals. If the combined signals includes only the data signal from the end unit, the path through which the pilot signal was sent is inoperative. If the combined signals includes only the pilot signal, the transmission path from the end unit over which the data signal is sent is inoperative.

Abstract: A monitoring apparatus and method are provided for a communication system in which a central office communicates to at least one end unit using intermediate remote nodes. The remote node receives signals from both the central office and the end units. Each remote node can be equipped with apparatus for monitoring the integrity of paths of the communication system. The monitoring apparatus can include a mixing device that mixes received signals to produce combined signals. The received signals generally include a pilot signal sent from the central office and a data signal sent from the at least one end unit. The state of the communication system is analyzed based on the combined signals. If the combined signals includes only the data signal from the end unit, the path through which the pilot signal was sent is inoperative. If the combined signals includes only the pilot signal, the transmission path from the end unit over which the data signal is sent is inoperative.

Abstract: This invention provides a method and apparatus for allocating pools of resources of a communication system to nodes and end users serviced by the nodes. The nodes are coupled to a communications network through interface units. The interface units are organized as a pool and may be either preassigned to each of the nodes or may be dynamically allocated to the nodes based on end user requests. All the nodes of the communication system uses a common frequency band. Each of the nodes is coupled to the communication network through a dedicated channel. Thus, bandwidth available to the end users are greatly expanded without expensive and complex upgrades to existing equipment.

Abstract: The present invention provides a local access network, having a switching node, a passive remote node connected to an optical network unit, a first optical fiber that provides a dedicated connection between the switching node and the passive remote node, and a second optical fiber that provides a dedicated connection between the switching node and the passive remote node. A first portion of a first fiber-optic cable containing the first optical fiber does not contain any part of the second optical fiber, such that there are independent paths from the switching node to the passive remote node.