Patent ID: 7522839
Filing Date: 2009-04-21
Classification: H04J

Abstract:
1. A method of upgrading an operational state of an optical node apparatus arranged on an optical transmission path of an optical communication system for transmitting a wavelength division multiplexed signal light, from an optical amplification repeating node to an optical add/drop multiplexing node, comprising: amplifying the wavelength division multiplexed signal light input to said optical node apparatus from said optical transmission path by a first optical amplifying section, branching said amplified wavelength division multiplexed signal light by an optical branching coupler into two to send one of the branched lights to a first optical path while sending the other branched light to a second optical path, selecting the light propagated through said first optical path by a first optical switch to amplify the selected light by a second optical amplifying section, and outputting said wavelength division multiplexed signal light amplified by said second optical amplifying section to said optical transmission path, to thereby operate said optical node apparatus as the optical amplification repeating node; and when the operational state of said optical node apparatus is switched from the optical amplification repeating node to the optical add/drop multiplexing node, connecting an optical add/drop multiplexing section having a function of dropping or adding a signal light of particular channel from or to the wavelength division multiplexed signal light and also including an output power adjusting section capable of adjusting the output power of signal light of each channel, between a set of connecting ports disposed on said second optical path, calculating an adjusting amount in said output power adjusting section of said connected optical add/drop multiplexing section utilizing the wavelength division multiplexed signal light which is branched by said optical branching coupler to be input via said second optical path, and controlling said output power adjusting section so that said calculated adjusting amount reaches a previously determined target adjusting amount, and after said control is completed, controlling said first optical switch so that the light propagated through said second optical path is selected.