Lucent Technologies Inc.

At&t Bell Laboratories

Alcatel Lucent

At+t Corp.

American Telephone & Telegraph Co., At&t Bell Laboratories

American Telephone and Telegraph, Co.

At&t Laboratories, Limited

At&t Company and At&t Bell Laboratories

Steven K Korotky

Rodney C Alferness

John J Veselka

Gadi Eisenstein

Thirumala R Halemane

Enrique A Marcatili

Fred L Heismann

Xiang Liu

Douglas Max Gill

Alan H Gnauck

Adriaan J De Lind Van Wijngaarden

Thomas L Koch

Randy Clinton Giles

Dusan Suvakovic

Suresh Goyal

Oliver Blume

Gary Weldon Atkinson

Daniel Charles Kilper

Edmond J Murphy

George Endicott Rittenhouse

David S Levy

John J Veselka, Jr

Jane E Zucker

Niloy K Dutta

Liyan Zhang

Rodney S Tucker

Glenn D Bergland

Neil Allan Jackman

John P Hickey

Eric S Tentarelli

Ronald J Capik

Jose F Hernandez-Gil

Timothy O Murphy

John M Hitchcock

Niraj Agrawal

A system and method for analyzing network power consumption is disclosed. The system and method for analyzing network power consumption includes the steps of specifying at least one service which will run on said network; defining a plurality of resources provisioned in the network, each having an associated power efficiency; associating a network path with the service; calculating a sum of the power efficiencies for the resources of the network path; and outputting the sum to a display device. The system and method for analyzing network power consumption is particularly useful for identifying power consumption efficiencies throughout a communication network.

System and method for analyzing network power consumption

An optical transport system (OTS) having a plurality of optical transponders (OTs) connected via one or more optical links and adapted to communicate with one another using respective rate-adaptive forward-error-correction (FEC) codes. In one embodiment, the OTS has a rate control unit (RCU) adapted to configure the OTs to dynamically adjust the rates of the FEC codes based on an estimated performance margin for each link between two respective communicating OTs to optimize the overall capacity of the OTS while maintaining an adequate, but not excessive, overall system margin.

Rate-adaptive forward error correction for optical transport systems

Apparatus for creating a communication signal, comprising a modulator adapted to: modulate a first and a second beam of continuous wave electromagnetic radiation with a source signal, assemble modulated portions of the first and second beams into a first electromagnetic radiation signal of interposed regular and alternate data bit sequences comprising asserted non return to zero coded data bits, each of the data bit sequences being interposed by unasserted data bits, in which mutually adjacent asserted data bits are conjoined, and assemble modulated portions of the first and second beams into a second electromagnetic radiation signal of interposed regular and alternate data bar bit sequences comprising asserted non return to zero coded data bar bits representing the unasserted data bits, each of the data bar bit sequences being interposed by unasserted data bar bits representing the asserted data bits, in which mutually adjacent asserted data bar bits are conjoined. Such apparatus for creating a communication signal, further comprising means for modulating the first electromagnetic radiation signal with the source signal to shift the phase of the alternate data bit sequences; and means for modulating the second electromagnetic radiation signal with the source signal to shift the phase of the alternate data bar bit sequences. Methods for creating communication signals.

Methods and apparatus for producing transmission failure protected, bridged, and dispersion resistant signals

A dual-output Mach-Zehnder modulator (MZM2) and configurations of optical transmitters based on the MZM2 which obviate the optical splitter that is typically used to provide keep-alive functionality in redundantly-connected, protected optical networks, SONET add-drop multiplexers, and optical IP routers. The configurations provide equivalent keep-alive utility at a reduced system cost relative to the prior art. The configurations also support enhanced Operations, Administration, Maintenance, and Provisioning (OAM&P) functionality at little to no additional cost relative to the prior art. Instead of being a direct copy of the service signal, the keep-alive of this configuration is an inverted version of the service signal. This inverted version of the service signal is supported at a client by utilization of means for detecting and righting the inverted signal. The inverted state of the signal on the protection path can be used as an inband indicator to notify the client in the event of a failure on the service path. This inband indicator requires little or no additional circuitry to accommodate. Another aspect of this invention allows the provisionable substitution of the inverted signal with a preemptive signal to support low-priority traffic when there is no fault on the service path S.

Provisionable keep-alive signal for physical-layer protection of an optical network

An add/drop arrangement using broadband optical couplers provides a low-loss, highly flexible add/drop capability for survivable wavelength division multiplexed (WDM) ring networks. At each node in the ring having the broadband optical coupler-based add/drop element, a portion of optical signal power of the entire WDM signal (i.e., all optical channels) is tapped off so that one or more optical channels of particular wavelengths can be dropped at the node. Information (e.g., data) to be added at the node is supplied in an optical channel that is added to the WDM signal via the broadband coupler. Because the add/drop element uses a broadband coupler, another portion of optical signal power of the WDM signal, including any added optical channels, passes through the node onto the ring. Depending on the specific ring topology being used with the broadband coupler-based add/drop arrangement, additional wavelength assignment and handling measures may be required. For example, certain ring topologies may experience interference between optical channels of particular wavelengths due to possible re-circulation of these optical channels beyond the add and drop nodes (e.g., after an optical channel passes its destination node). According to one illustrative embodiment, a node is equipped to perform wavelength conversion and/or wavelength suppression to prevent undesirable re-circulation of optical channels.

Optical add/drop arrangement for ring networks employing wavelength division multiplexing

In a telecommunications network, such as an optical mesh network, satisfying a demand from a start node to an end node, the network is automatically provisioned from a service path to a restoration path after a failure occurs in the service path. Each affected node in the network eventually receives an indication of the occurrence of the failure in the service path. If the node is an intermediate node of the service path, then the node transmits a failure message to its next node along the service path. If the node is the end node of the service path, then the node transmits a restore message to its previous node along the restoration path. If the node is an intermediate node of the restoration path, then the node transmits a restore message to its previous node along the restoration path. In addition, the node reconfigures its cross-connect for the transition from the service path to the restoration path.

Network auto-provisioning and distributed restoration

A method and apparatus for deriving insertion losses for connections in a single-stage optical cross-connect. The optical cross-connect comprises a number (N) of input ports, a number (M) of output ports and an on-board controller. A memory is provided on the on-board controller for storing N loss parameters for the N input ports and M loss parameters for the M output ports. A modeled insertion loss for a connection between any input port and any output port can be derived from the loss parameters associated with the input and output ports.

Method and apparatus for determining loss parameters for optical cross-connects

A light source for generating many precisely spaced wavelength channels, based on the periodic modulation of light. CW light is periodically amplitude modulated and then coupled to a non-linear fiber where it undergoes additional modulation by the process of self-phase modulation or other non-linear effects. In a general embodiment of the multi-wavelength source (MWS), an optical modulator driven by a periodic electromagnetic signal imposes periodic amplitude modulation on light from a single longitudinal mode CW laser. The light is then coupled to a non-linear medium with an intensity dependent refractive index where it generates higher order spectral sidebands by the process of self-phase modulation and/or other non-linear effects. The frequency spacing between the spectral components is equal to the repetition rate of the modulation. The shape of the spectrum (i.e. the relative amplitudes of the spectral components) can be modified by adjustments to: the amplitude modulated waveform; the optical power of the waveform when coupled to the non-linear medium; and/or characteristics of the non-linear medium such as the non-linear refractive index, the length and the dispersion.

Multi-wavelength laser source

An optical device having a first substrate having a fast optical axis and a slow optical axis and a first end and a second substrate having a fast optical axis and a slow optical axis and a second end, the second end is positioned adjacent to the first end such that the fast optical axis of the first substrate is coupled to the slow optical axis of the second substrate and the slow optical axis of the first substrate is coupled to the fast optical axis of the second substrate, thereby permitting an optical signal to pass between the first and second substrates. The first substrate and the second substrate have substantially equal length to thereby substantially eliminate polarization dispersion.

Polarization dispersion compensation for optical devices

Spectral broadening over a large range using PM is achieved by a lightwave source without the need for a large phase modulation index and without expending a large amount of modulator RF drive power. In this lightwave source, a laser output signal is externally phase modulated by one or more modulation signals. The phase modulation employs one or more frequency drive signals (i.e., the modulation signals) each of whose amplitude is judiciously selected to produce an output spectrum having substantially equal spectral components over a predetermined range of frequencies. The predetermined frequency range is centered about the source frequency for the laser and resembles a comb. Each frequency drive signal is also selected to have a frequency (or frequency spacing from other drive signals) so that adjacent spectral components in the output spectrum of the modulated signal are produced with a frequency spacing which exceeds the SBS interaction bandwidth at the transmission wavelength of interest.

Multifrequency lightwave source using phase modulation for suppressing

An optical pulse generator for producing a soliton pulse train having a modulator which amplitude and phase modulates an optical frequency output of a continuous optical wave source. The modulator is driven by first and second harmonically related continuous sinusoidal waves from first and second CW voltage sources and the generator includes a pulse compression means for producing at the output of the generator a soliton pulse train.

Optical soliton generator

An interferometric modulator comprising a substrate of titanium-doped lithium niobate (Ti:LiNbO.sub.3) having top and bottom surfaces and a waveguide formed in the top surface is disclosed. A conductive layer is formed on the bottom surface of the substrate and electrically coupled to a top-surface ground plane or simply to ground potential. The bottom surface conductive layer functions to thermally stabilize the modulator during operation.

Electrooptic device structure and method for reducing thermal effects in

External modulation is accomplished in a dual waveguide device wherein substantially identical input optical beams are supplied to the waveguides and wherein each waveguide through its electrode is subject to individual, mutually exclusive control. Modulation signals are applied to each waveguide via its separate electrode. Control signals are applied to each waveguide for adjusting the modulation chirp parameter to a desired fixed, non-zero value. Typically, the desired value of the chirp parameter is one which provides the lowest fiber dispersion penalty for the system. Modulated lightwave signals emerging from the waveguides are combined to form a single output signal suitable for transmission over an optical fiber. In one embodiment, Mach-Zehnder interferometer having separately controllable waveguides has its input coupled to a CW laser. Both III-V semiconductor and Ti:LiNbO.sub.3 Mach-Zehnder interferometers have been utilized as external modulators in accordance with the principles of the present invention.

Tunable chirp, lightwave modulator for dispersion compensation

It has been determined that optical fibers possess a small amount of nonlinearity and, therefore, they are not exactly linear waveguides. This small amount of nonlinearity enables certain special pulse shapes to establish themselves and travel long distances without changing shape. These special pulse shapes are called solitons. This invention relates to a device for generating solitons by amplitude modulating an optical signal with separate in-phase electrical signals of different harmonically related frequencies. Specifically, an amplitude modulator such as a Y junction Mach-Zehnder interferometer has multiple sets of distributed electrodes. The interferometer has a set of electrodes for each electrical signal of a specific frequency. Thus, if three separate signals of harmonically related frequencies are used to amplitude modulate an optical signal, then the interferometer has three sets of electrodes located between the Y junctions of the Mach-Zehnder interferometer. The structure of a separate set of electrodes for each of the signals results in a soliton generator which avoids the prior art problem of signal loss caused by combining many high frequency signals into a composite signal and the resulting need for a relatively expensive amplifier capable of uniformly amplifying the multioctive composite signal.

Soliton generator

Briefly, in the invention a photodetector and an optical amplifier are integrated in the same semiconductor chip. The optical amplifier and the photodetector are positioned side-by-side on the same chip. A portion of the electromagnetic energy carried in the evanescent tail of the optical mode is detected by the photodetector for monitoring the average output power of the optical amplifier. Current confinement and lateral index guiding can be provided by Fe or Ti doped semi-insulating layers of InP. The side-by-side arrangement enables the detector to monitor the output power of the optical amplifier without degrading the output power of the optical amplifier.

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Toms River, NJ, United States of America

Steven K Korotky