Lucent Technologies Inc.

Bell Telephone Laboratories

Nathan Myron Denkin

Wenhua Lin

Daniel A Fishman

Gerard T Lingner, Iii

Wei-Chiao William Fang

Martin Zirngibl

Daniel Yousef Al-Salameh

Dieter Werner

Tek-Ming Shen

Peter Klaus Runge

Magaly Spector

Fatimah Shehadeh

Matthias Richard Feulner

Thomas F Link

Jiong Ma

Maria F Mendez

Mingjuan Zhu

Alexander Golubchik

Bharat P Sinha

A method, apparatus and system for controlling power transients in amplified optical transmission system includes, in response to the detection of a power transient in an optical signal, varying a gain of at least one amplifier to correct for a time delay in a gain response associated with a gain change in an amplifier. Alternatively, the method, apparatus and system further include in response to the detection of the power transient, adjusting the gain of at least one amplifier to correct for a change in signal power.

Method, apparatus and system for controlling the effects of power transients in optical transmission systems

A method and system in accordance with the present invention greatly reduces the gain error due to Raman gain tilt for individual channels in an optical communication system during a transient event by determining a shift in average power (and thus wavelength) and using the determined shift to alter the average gain in the optical communication system. In various embodiments of the present invention, the average gain of the optical communication system is altered by altering the average gain of an amplifier in the optical communication system. In alternate embodiments of the present invention having an in-line optical filter, the average gain of the optical communication system may be altered by altering the filtering of the optical channels in the optical communication system.

Method and system for reducing Raman gain tilt error

A method, apparatus and system for controlling power transients in a Raman-amplified optical transmission system includes, in response to the detection of a power transient in an optical signal, varying the gain of at least one dispersion compensating module (DCM) in the Raman-amplified optical transmission system to correct for a change in signal power caused by the power transient.

Method, apparatus and system for controlling power transients in a Raman-amplified optical transmission system

A unique sensor is used to detect a transmission impairment that may have affected incoming optical channel signals. The sensor, more specifically, selects a group of the incoming channel signals and generates a first power signal, P, over the selected group of signals and generates a second power signals, P, over a weighted version of the selected group of channel signals. The sensor then generates, as a function of the first and second power signals, Pand P, a signal indicative of whether the particular transmission impairment affected the levels of individual ones of the incoming channel signals. If so, then control apparatus offsets the impairment accordingly.

Apparatus for detecting raman gain in an optical transmission system

An integrated wavelength router for use in a wavelength division multiplexing system is disclosed. Input waveguides deliver a plurality of optical signals to a first slab coupler which is in turn coupled to an optical grating waveguide. A second slab coupler is coupled to the output of the optical grating waveguide which is in turn coupled to output waveguides. The input and output waveguides transmit data channels of the wavelength division multiplexing system and include out-of-band signals such as a supervisory signal or a pilot signal with different channel bandwidths. WDM systems utilizing the router of the present invention can reduce power losses and therefore increase the span length of the wavelength division multiplexing system.

Optical multiplexer/demultiplexer arrangement for WDM signals having in-band and out-of-band signal components

An apparatus and method are described for controlling response to power transients in an optically amplified wavelength division multiplexed (WDM) network when WDM optical channels are added and dropped, during network reconfigurations, during failure events, and so on. In one embodiment, a variable bandwidth filter circuit operates at a first prescribed bandwidth during a first time period &tgr; to detect a change in signal power (i.e., power transient) caused by a transient event, and operates at a second prescribed bandwidth that is less than the first prescribed bandwidth after the first period of time elapses, e.g., &tgr; &plus;&Dgr;&tgr;, to substantially suppress low level signal variations, such as remnants of the power transient. In this way, the power transient related to the actual transient event will be preserved to trigger control circuitry, e.g., amplifier gain control based on input power changes, while the remnants will be filtered out to prevent unwanted responses by the control circuitry, e.g., remnants misinterpreted as actual transient events.

Method and apparatus for stabilizing transient control in amplified optical networks

The spectral distortion introduced by stimulated Raman scattering (SRS) in an optical fiber transmission system has been determined to always be linear on a dB/nm scale and depend solely on the total input power and not on the input power distribution. By maintaining the total input power to the fiber constant, the resulting Raman gain tilt may be compensated for or canceled by using an optical filter.

Raman gain tilt equalization in optical fiber communication systems

A protection facility is provided for use in an optical communications node that communicates with another optical communications node via first and second bidirectional communications paths respectively serving as a service path and protection path, in which a filter filters signals respectively received over the service and protection paths and generates a main signal and a complementary signal for each of the paths. A control unit then generates a Loss of Signal (LOS_A) indication for the service path if a SUM signal or DIFF signal respectively derived as a function of a sum of the main and complementary signals generated for the service path and difference between the main and complementary signals generated for the service path is less than a respective threshold value. A switch then invokes protection switching responsive to the presence of the LOS_A indication.

Optical protection switch employing an interference filter

The monitoring of regulated redundant power supplies is enhanced by returning to each power supply a feedback (sensed) voltage signal that is indicative of the voltage level that the respective power supply is outputting and the voltage level supplied to a system load. In one embodiment, a feedback signal that is supplied to a power supply as the sensed signal is derived using a voltage divider network across the output of the power supply and a common connection at which the outputs of the power supplies are &ldquo;Ored&rdquo; for delivery to the system load. In this way, each power supply regulates its output voltage as a function of the level of the feedback signal and the level of a respective preset signal.

Redundant regulated power supply system with monitoring of the backup power supply

The temperature of a thermo-electric cooler that is used to cool a laser is effectively controlled using a monitor which accurately and continuously measures the temperature of the thermo-electric cooler and using apparatus that determines the difference between the measured temperature and a desired thermo-electric cooler temperature. A discriminator circuit causes the thermo-electric cooler to enter (a) a heating cycle when such difference is below a first reference level or (b) a cooling cycle when such difference reaches a reaches a second reference level. Power consumption within the associated cooling/heating system is also accurately controlled using a pulse width modulated power supply to provide the voltage signal that drives the thermoelectric cooler.

Efficient thermoelectric controller

The present claimed invention improves on the conventional comb and multiple router approach by making multiple use of a single router by using interleaved groups of wavelengths that enter through different entrance ports and exit through different groups of exit ports of the same router. This permits better separation (lower crosstalk) between adjacent channels, greatly reduced temperature sensitivity, small physical size and lower cost. With these improvements, a large number of wavelength add/drop sites may be cascaded in WAD/WDM systems.

Interleaved wavelengths multi/demultiplexer with multiple-input-ports and multiple-output-ports for wavelength add/drop WDM systems

A bi-directional protection facility is provided in an optical communication system in which an optical communications node communicates with another optical communications node via first and second bi-directional communications paths respectively serving as a service path and protection path, and in which a filter at each node processes signals respectively received over the service and protection paths and generates an in-band signal and out-of-band signal for each of the paths. A control unit then generates a Loss of Signal indication for the service path if the level of the out-of-band signal is found to be greater than the level of the in-band signal and protection switching is effectuated as a function of the presence of the control signal. In addition, an outgoing signal to the other communications node is interrupted for a sufficient period of time to cause a LOS at that node and thus trigger protection switching thereat to complete the bi-directional switching process.

A facility in a communication system associates a unique identification signal with each currently active communications channel and then transmits the unique identification signal and associated information signals within the respective channel. In this way, apparatus that receives the transmitted signals may determine the number of channels that are active based on the number of the identification signals it receives and then output the received signals at a power level determined as a function of that number.

Apparatus and method for automatically provisioning power on a per

The invention relates to apparatus for precisely aligning an optical device, i.e., a light source or receptor, to an optical fiber. In one embodiment, the apparatus comprises a header (10) having a plateau (11) for mounting the device (15) and a trough (12) for positioning of the optical fiber (19). The depth (D) of the trough is precisely configured so that the alignment process is limited to adjustment in only one direction (L-L'). A second embodiment (30) allows for the hermetic enclosure of the optical device and adjacent section of optical fiber while providing the same alignment advantage.

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Aberdeen, NJ, United States of America

Nathan Myron Denkin