Nortel Networks Corporation

Toby J Reid

Kevan Peter Jones

Simon P Parry

Alan Robinson

Jonathan Paul King

Robert William Keys

Mark R Hinds

Nigel Edward Jolley

Barrie Flintham

Mark E Bray

James Regan

Martin P Poettcker

Robert A Baker

Roger M Gibb

Alan A Solheim

Joseph Mun

In a WDM optical transmission system employing optical amplifiers in its transmission path, a supervisory signal channel, used for monitoring and controlling the operation of the amplifiers and spectrally separated from the data transmission, may be multiplexed with the data. A construction of amplifier is disclosed which is capable of being upgraded with an upgrade of the transmission system to include additional data handling capacity, for instance data transmission in an additional waveband and/or in the opposite direction, without interruption of the pre-upgrade data transmission path through the amplifiers. This is accomplished by the use of channel dropping and insertion filters disposed so that the amplifying data transmission path extends via the drop/insertion channel of those filters.

Optical amplifiers

Growing community of inventors

Torquay, United Kingdom

Toby J Reid