Xtera Communications, Inc.

Corning Incorporated

Pavle Gavrilovic

Mohammed N Islam

Michael J Freeman

Alan Frank Evans

Stuart Gray

Herve A Fevrier

Andrej B Puc

Andrzej S Kaminski

Ricardo Saad

Ashiqur Rahman

Michel W Chbat

Hyunchin Kim

James E Newby

Peter J Goudreau

In one embodiment, an optical amplifier includes a gain medium operable to receive a plurality of signals each having a center wavelength and a noise figure associated with at least a portion of the amplifier and varying as a function of wavelength. At least two of the plurality of signals have launch powers that are a function of a magnitude of the noise figure measured at or near the center wavelength of that signal.

Optical amplification using launched signal powers selected as a function of a noise figure

In one aspect of the invention, a system operable to reduce degradation of an optical signal to noise ratio where signals having multiple wavelengths are communicated over a common optical link includes an amplifier assembly operable to introduce to a lower communication band a first gain and to introduce to a higher communication band a second gain that is different from the first gain. In addition, the system is operable to introduce a variable gain tilt into at least one of the communication bands. The different gains introduced to the higher and lower bands and the variable gain tilt introduced into at least one of the bands result in a reduction of a degradation of optical signal to noise ratio that could otherwise be caused by wavelength dependent attenuation when the communication bands are combined and communicated over an optical link.

Method and system for reducing degradation of optical signal to noise ratio

A Raman fiber amplifier includes: a transmission fiber; at least one optical pump providing optical pump power to the transmission fiber; and at least one pump power detector; at least one signal detector detecting signal power propagating through the transmission fiber. The Raman fiber amplifier also includes a controller that adjusts the pump power provided by the pump to adjust, gain, or signal power provided by this Raman fiber amplifier.

Gain control in Raman amplifiers

In one aspect of the invention, a control system for use in an optical amplifier includes a plurality of control legs, each operable to receive one of plurality of portions of an optical signal, wherein each of the plurality of portions comprises a different percentage of the optical signal. The system further includes a plurality of registers, each associated with one of the control legs and each operable to store a value proportional to the portion of the optical signal communicated in the associated control leg. The system also includes a controller operable to select one of the values stored in one of the plurality of registers and to scale that value by a scaling factor to generate a scaled value, wherein the scaling factor is determined at least in part by the percentage of the optical signal associated with that value. The controller is operable to generate, based at least in part on the scaled value, a control signal operable to affect the gain of the amplifier.

Method and apparatus for amplifier control

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Allen, TX, United States of America

Pavle Gavrilovic