Patent ID: 6476946
Filing Date: 2002-11-05
Classification: H04J

Abstract:
A method of dropping and adding channels for use in wavelength-division multiplex optical transmission, the method comprising:transmitting information using a plurality of channels, wherein a portion of said channels are assembled to form an upstream multiplex, said channels of said upstream multiplex being spectrally distributed, and said channels of said upstream multiplex being separated in a selection module into at least one dropped group and one transit group, diverting said dropped group to a lateral circuit, at least during reinsertion periods, diverting at least a part of said dropped group to an amplifier system having a progressive saturation gain, and assembling said transit group with said part of said dropped group to form a downstream multiplex, wherein the gain of said amplifier system is sufficient to create an optical wave in said lateral circuit and said amplifier system at the same time as said part of said dropped group, said selection module being adapted to enable said optical wave to circulate in a closed loop further comprising said selection module and said optical wave constituting a loop wave, and a preferred wavelength for said loop wave that is outside a spectrum occupied by said channels.