Patent ID: 6501575
Filing Date: 2002-12-31
Classification: H04J

Abstract:
A method for routing an optical signal in an optical transmission system using wavelength multiplexing and including several channels, and at a transmitting node of said system:the information content of each channel is transmitted onto its own wavelength by modulating a laser transmitter producing the wavelength in question, optical signals received from the laser transmitter are conducted to their respective inputs in a coupler, which is a non-wavelength-selective component and which combines the optical signals onto the same optical fibre as an optical sum signal, and in a receiving node: the optical sum signal received from the optical fibre is separated into different wavelengths by using a wavelength-selective optical separation component, whereby a predetermined wavelength is obtained from each output port of said separation component, the method comprising the steps of: changing in the transmitting node, by using at least one laser transmitter, a first wavelength to a second wavelength, both of said wavelengths being available in the optical transmission system, so that after said change the second wavelength carries the information content of the first wavelength and the first wavelength carries the information content of the second wavelength, obtaining in the receiving node the information content of the first wavelength through an output port to which the second wavelength was originally routed, and obtaining in the receiving node the information content of the second wavelength through another output port to which the first wavelength was originally routed.