Dorsal Networks, Inc.

Corvis Corporation

Broadwing Corporation

Sowilo Networks, Inc.

William Shieh

Vladimir Petricevic

Thomas R Clark, Jr

M Imran Hayee

Thomas S Clark

Bo Pedersen

Michael L Dennis

Cathal Mahon

Zhengchen Yu

Quan Wang

Nandakumar Ramanujam

Antonios Seas

Roger Dorsinville

Nadakumar Ramanujam

A device and method for reducing amplified Rayleigh backscatter at a Raman pump. A pump assembly for an optical amplifier includes a set of pump radiation sources for Raman pumping an optical transmission span. Each pump radiation source is adapted to produce radiation having a pump wavelength and a pump power. The optical transmission span is adapted to provide Raman amplification of an optical data signal when pumped by the set of pump radiation sources. At least one optical isolator is selectively located between at least one selected pump radiation source and the optical transmission span to reduce amplified Rayleigh backscatter at the pump wavelength of the selected pump radiation source from feeding back into the selected at least one pump radiation source.

Device and method for reducing pump laser instability due to amplified rayleigh scattering feedback

A method for maintaining amplifier saturation in a wavelength division multiplexed (WDM) optical network having a plurality of sub-bands, each sub-band including at least two signal channels which carry respective data signals, and a plurality of substitute signal transmitters, each substitute signal transmitter generating a substitute signal and corresponding to a respective one of the plurality of sub-bands, includes identifying signal channels having a predetermined characteristic within each of the plurality of sub-bands. A substitute signal transmitter is turned on if the sub-band corresponding to the substitute signal transmitter includes a predetermined number of signal channels having said predetermined characteristic. The data signals and the substitute signals are combined into a WDM signal, and the WDM signal is transmitted over an optical transmission fiber.

Methods of signal substitution for maintenance of amplifier saturation

A wavelength division multiplexed (WDM) optical network includes a plurality of optical transmitters, each optical transmitter generating a data signal sent over a respective one of a plurality of signal channels, the plurality of signal channels being divided into a number of sub-bands where each sub-band includes at least two signal channels, and a plurality of substitute signal transmitters, the number of substitute signal transmitters being equal to the number of sub-bands, each substitute signal transmitter generating a substitute signal which provides loading in a corresponding sub-band. The WDM optical network also includes a combining circuit which combines the data signals output from the plurality of optical transmitters and the substitute signals output from the plurality of substitute signal transmitters into a WDM signal, and an optical transmission fiber which receives the WDM signal from the combining circuit.

Terminals having sub-band substitute signal control in optical communication systems

A method of amplifying optical signals comprising providing a plurality of input radiation signals into the inputs of a P&#xd7;V coupler, each of the input radiation signals having a respective input radiation profile having a set of pump wavelengths and pump powers corresponding to the respective wavelengths, wherein at least one set is different from at least one other set; providing V output pump radiation profiles from the outputs of the P&#xd7;V coupler; and amplifying an optical data signal by coupling at least one of the V output pump radiation profiles with the optical data signal, wherein at least one of the V output pump radiation profiles has a different power than at least one other of the V output pump radiation profiles.

Pump assembly employing coupled radiation sources for multiple fibers

A system and method of providing a transmission span for a telecommunications link based on a remote Er-doped fiber amplification scheme is provided, where a transmission span comprises first through third segments each respectively comprising first-third optical fibers having first-third fiber lengths and first-third physical properties. The first and third segments are optically coupled to opposing ends of the second segment. At least one of the first and third physical properties is different from the second physical property, where the first segment provides low nonlinearity, the third segment provides distributed gain, and the second segment compensates for the dispersion of the first and third segments. The span also includes a fourth optical fiber that is doped with a non-zero concentration of Er, and is disposed at a location in the span for remote pumping to provide discrete amplification of the optical signal. The location can be within the first segment, within the second segment, within the third segment, at an interface between the first and second segments, and/or at an interface between the second and the third segments.

Method and system for dispersion maps and enhanced distributed gain effect in long haul telecommunications using distributed and remotely pumped erbium-based amplification

A pump assembly for an optical amplifier includes a plurality of pump radiation sources, each pump radiation source producing radiation at a respective one of a first number of pump wavelengths. A coupler is optically coupled to each of the plurality of pump radiation sources, receives each of the first number of pump wavelengths from the plurality of pump radiation sources, and outputs each of the first number of pump wavelengths to each one of a second number of outputs. The pump assembly also includes a plurality of pump signal combiners, each pump signal combiner optically coupled to a respective one of the second number of outputs of the coupler and receiving each of the first number of pump wavelengths output from the coupler. Each pump signal combiner placing each of the first number of pump wavelengths output from the coupler in co-propagation with a respective one of a plurality of data signals propagating on a respective one of a plurality of optical fibers.

Shared forward pumping in optical communications network

An optical coupler system is described. The optical coupler system is for coupling radiation from a plurality of radiation sources. The optical coupler system comprises a first optical coupler having at least a first and a second input and a first and a second output. The optical coupler also comprises a second optical coupler having at least a first and a second input and a first and a second output, wherein the first and second outputs of the first optical coupler are connected to the first and second inputs, respectively, of the second optical coupler via first and second optical links, and wherein the first and second links provide different optical paths between the first and second optical couplers such that portions of radiation energy that is input to the first input of the first optical coupler are combined incoherently at the first output of said second optical coupler.

Balanced coupler for radiation sources

A system and method of providing a transmission span that compensates for signal attenuation, dispersion, and nonlinearity of an optical signal communicated between two line units of a transmission link includes dividing the transmission span into a plurality of fiber segments and selecting a particular fiber for each of the segments. The fiber selection and arrangement of fibers within the span can be selected in accordance with the nonlinearity, dispersion conditions, and distributed gain conditions of the constituent fibers. In a three segment map, the first segment can provide low non linearity, the third segment can provide distributed gain, and the second segment can compensate for the dispersion of the first and third segments. The span can be used, e.g., for distributed Raman amplification. The span can alternatively include a two segment map, a four segment map, or a map with additional segments.

Method and system for dispersion maps and enhanced distributed gain effect in long haul telecommunications

An optical amplifier. The amplifier includes a plurality of pump radiation sources, each pump radiation source adapted to produce radiation having a set of pump wavelengths and pump powers corresponding to the respective pump wavelengths, wherein at least one set is different from at least one other set. The amplifier also includes a plurality of pump radiation combiners and a coupler. The coupler is optically coupled to the outputs of the pump radiation combiners, receives the coupled radiation from the pump radiation combiners and outputs pump radiation profiles to respective coupler outputs. The amplifier also includes pump-signal combiners, each optically coupled to a respective coupler output of the coupler outputs, which are adapted to couple an optical signal with the respective pump radiation profiles.

A method and system for equalizing Q performance of a wideband, Raman-amplified optical communication system are disclosed. Wideband, Raman-amplifed systems suffer significant performance degradation from nonlinear effects in shorter wavelength channels. Absent compensation, the shorter wavelength channels limit system performance and restrict the amount of launch power that can be employed for the optical data signals in each wave division multiplexed channel. Careful design that employs increased channel spacing in the nonlinear region of the bandwidth can offset the increased nonlinear effects, thereby improving the worst channel's Q performance and permitting high launch power without unacceptable Q performance.

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Columbia, MD, United States of America

William Shieh