Patent ID: 7248799

Claim:
A method of controlling the power of optical signals in a transparent switching node (Ni) of an optical communication network that switches bands of wavelengths, said node (Ni) comprising demultiplexing means ( 1 ) for feeding demultiplexed optical signals to switching means ( 4 ) for feeding demultiplexed optical signals to multiplexing means ( 6 ), said method comprising the steps of i) measuring the input optical power of the optical signals at one output at least of said switching means ( 4 ), ii) comparing the measured input optical power to a selected first threshold and generating instructions representative of the result of said comparison, and iii) controlling the optical power of the signals coming from said switching means ( 4 ) as a function of the instructions received, so that the optical power of the signals at the input of said multiplexing means ( 6 ) is maintained substantially constant, which method is characterized in that in the event of a request for said switching means ( 4 ) to switch bands of wavelengths or in the event of a comparison result representative of a fault, the input of said multiplexing means ( 6 ) is fed with a selected auxiliary optical power and the optical power downstream of the output of said switching means ( 4 ) is attenuated, so that the optical power of the signals at the input of said multiplexing means ( 6 ) is substantially constant.