Lucent Technologies Inc.

Jianhui Zhou

Bernd Teichmann

Dirk Bode

Guido Hermann Hunziker

Martin Zirngibl

John L Zyskind

James W Sulhoff

Daniel A Fishman

Atul Kumar Srivastava

Yan Sun

Dieter Werner

Stan Lumish

Gabriela Livescu

Matthias Richard Feulner

Fatimah Shehadeh

Christian Raabe

Matthias Berger

The number of optical channels that may be used to transmit information/data is greatly enhanced using an optical transmission facility having a transmitter that outputs optical signals having respective wavelengths within a first bandwidth, e.g., the C band, combines the latter signal with an optical signal having a wavelength between the first bandwidth and a second bandwidth, e.g., the L-band, and, using a non-linear frequency converter, processes the combined signal to form at least optical signals having wavelengths within the second bandwidth that correspond with the wavelengths of the optical signals within the first bandwidth. In this way, equipment designed for the C band may also be used to process optical signals with another, second band.

Channel band conversion apparatus for optical transmission systems

In an optically amplified wavelength division multiplexed (WDM) system having a WDM signal comprising a plurality of optical channels, the per-channel gain of the optical channels is kept relatively constant despite changes in input power at the optical amplifier, such as when individual optical channels of the WDM signal are added and dropped. More specifically, gain of an optical amplifier is controlled by controlling the amount of pump power supplied to the optical amplifier as a function of changes in input power which are measured in a feed-forward monitoring path. The amount of pump power for effecting gain control is adjusted according to a scaled relationship to the measured input power of the optical amplifier. By controlling the pump power directly in response to changes in input power, gain of the optical amplifier can be controlled within a sub-microsecond time scale from the time that a change in input power is detected. Moreover, by maintaining relatively constant per-channel gain in an amplified WDM signal despite changes in input power at the optical amplifier, power excursions are substantially reduced in surviving optical channels of the WDM signal, i.e., those at the output of the optical amplifier.

Fast gain control for optical amplifiers

The present invention relates generally to the field of optical transmission and particularly to a method and a system for controlling optical amplification in wavelength division multiplex optical transmission. WDM systems currently under development will have eighty or more channels, i.e., modulated optical signals with different wavelengths (known as Dense Wavelength Division Multiplexing, DWDM). These DWDM systems are demanding optical amplifiers which, especially considering the cascadation of a plurality of optical amplifiers along the transmission path of the DWDM system, have only very limited tolerances in certain parameters. Among these parameters gain flatness and gain tilt are of special importance. The present invention discloses a method and a system which make use of auxiliary optical signals having a given power level which is equal for all auxiliary signals. Differences in the power levels of the auxiliary signals after optical amplification are used for the control of the optical amplifiers of the WDM system.

Method and system for controlling optical amplification in wavelength division multiplex optical transmission

An optical amplifier is adapted to cancel the Raman gain of an optical transmission path that degrades those optical signals occupying the low end of the bandwidth such that the power is transferred from the latter signals to the optical signals occupying the high end of the bandwidth. More specifically, the optical amplifier adjusts the gain that it applies to the optical signals so that it favors the signal components at the low end of the bandwidth.

Optical amplifier arranged to offset Raman gain

An optical amplifier that receives an optical signal at an input of the optical amplifier is arranged so that it amplifies the signal and then adjusts the level of the amplified input signal to a predetermined level. The optical amplifier, which includes a filter to substantially decrease the wavelength dependence of the optical amplifier, then amplifies the adjusted signal and supplies the resulting signal to an output.

Broadband flat gain optical amplifier

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Freehold, NJ, United States of America

Jianhui Zhou