Telefonaktiebolaget Lm Ericsson (publ)

Google Inc.

Pirelli Cavi E Sistemi S.p.a.

Pirelli & C. S. P. A.

Pgt Photonics, S.p.a

Raffaele Corsini

Attilio Bragheri

Giulia Pietra

Danilo Caccioli

Roberto Magri

Ernesto Ciaramella

Emma Matarazzo

Andrea Peracchi

Marco Romagnoli

Luciano Socci

Michele Midrio

Chromatic dispersion (CD) processing apparatus comprises an equalizer loop comprising: a frequency domain equalizer (FDE) arranged to receive samples of an electrical representation of an optical communications signal having CD and to apply CD compensation to the samples, to form dispersion corrected samples having a residual CD value; a time domain equalizer arranged to receive the corrected samples and to generate a representation of a channel linear transfer function of the signal from the corrected samples, to generate and transmit a monitoring signal comprising said representation; optical performance monitoring apparatus arranged to receive the monitoring signal and to estimate the residual CD value; and a processor arranged to receive the estimated residual value and to compare it to a threshold value and to generate and transmit to the FDE an estimation signal comprising the estimated value unless it is less than the threshold.

Chromatic dispersion processing apparatus and method

A method of monitoring a differential group delay (DGD) of an optical communications signal having a polarisation multiplexed modulation format is described. The method includes the operations of receiving a signal and performing analogue to digital conversion of the signal to generate a digitised signal corresponding to one polarisation of the signal and to generate another digitised signal corresponding to another polarisation of the signal, and applying a polarisation mode dispersion(PMD) compensation to each of the digitised signals. The method further includes the operations of obtaining an indication of the channel transfer function of the optical communications signal, determining a DGD in dependence on the indication of the channel transfer function, determining a delay between the PMD compensated digitised signals, subtracting the delay from the DGD to obtain a corrected DGD, and generating and transmitting a monitoring signal with an indication of the corrected DGD.

Optical signal monitoring method and apparatus

A Raman amplifier includes at least a first and a second optical Raman-active fiber disposed in series with each other. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of said first and second group of frequencies extends over a pump frequency range having a width of at least the 40% of the Raman shift. The minimum and the maximum frequency in each of said first and second group of frequencies differ with each other of at most the 70% of said Raman shift.

Multi-stage raman amplifier

A Raman amplifier comprises at least a first and a second optical Raman-active fiber disposed in series with each other. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of said first and second group of frequencies extends over a pump frequency range having a width of at least the 40% of the Raman shift. The minimum and the maximum frequency in each of said first and second group of frequencies differ with each other of at most the 70% of said Raman shift.

Multi-stage Raman amplifier

A Raman amplifier having at least a first and a second optical Raman-active fiber disposed in series with each other is disclosed. A first pump source is connected to the first Raman-active fiber, and is adapted for emitting and coupling into the first Raman-active fiber a first pump radiation including a first group of frequencies. A second pump source is connected to the second Raman-active fiber, and is adapted for emitting and coupling into the second Raman-active fiber a second pump radiation including a second group of frequencies. The whole of the first and second group of frequencies extends over a pump frequency range having a width of at least 40% of the Raman shift. The minimum and the maximum frequency in each of the first and second group of frequencies differ from each other by at most 70% of the Raman shift.

Device for performing a parametric process, comprising a substantially periodic photonic crystal structure comprising a plurality of unitary cells each comprising

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Milan, Italy

Raffaele Corsini