Communications network

Abstract

A communications network wherein first and second optical signals can be launched into an optical fiber in respective first and second regions of a transmission window such that controllable filters can be used to selectively recover the first and second optical signals. This partitioning of the transmission window allows two incompatible optical signals to coexist in the same optical fiber.

Description

PRIORITY CLAIM[0001]The present application is a National Phase entry of PCT Application No. PCT / GB2012 / 000528, filed Jun. 18, 2012, which claims priority from EP Patent Application No. 11250602.7, filed Jun. 20, 2011, and GB Patent Application No. 1112713.1, filed Jul. 25, 2011, said applications being hereby incorporated by reference herein in their entireties.TECHNICAL FIELD[0002]The present application relates to an optical communications network and in particular to an optical communications network which can support optical signals of different formats.BACKGROUND[0003]Conventional optical communication networks operate by sending light pulses of a predetermined period, for example such that a pulse represents a ‘1’ and no pulse represents a ‘0’. This technique enables signals to be sent at data rates of up to 10 Gb / s and wavelength division multiplexing (WDM) techniques can be used to send multiple signals over a single fiber. Dense WDM (DWDM) enables up to 160 wavelengths to ...

AI Technical Summary

Benefits of technology

This patent describes an optical network that allows different optical signals to be transmitted in the same fiber. This flexibility allows network operators to easily expand and upgrade their networks, using different types of optical signals. For example, a portion of the transmission window can be used for conventional wavelengths and a different portion can be reserved for advanced transmission technologies. Over time, the network can be upgraded as new technologies become available. This flexible deployment path allows network operators to invest in new transmission capacity as technologies improve and customer demand increases. Overall, this patent enables network operators to have more flexibility and options for upgrading their networks.

Problems solved by technology

One of the transmission phenomena present in optical fibers is chromatic dispersion, which causes the transmitted pulse to spread out, such that it becomes difficult to recover the transmitted signal at the receiver.

The effects of dispersion can be mitigated by installing dispersion compensating modules (DCMs) into the network, but this adds to the cost and the complexity of the network.

As data transmission rates increase further, for example beyond 100 Gb / s, then the optical signals required to transmit such data rates may not fit into the grid of wavelengths that are defined in the DWDM specifications.

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