Patent ID: 7136584

Claim:
An optical output power automatic attenuation circuit for an optical communication apparatus provided with a plurality of transmission sections each outputting a light of previously set power and a reception section including a plurality of optical input terminals which are connected to respective output terminals of said plurality of transmission sections via optical fibers on one-on-one level, wherein the power of the light input to each of the optical input terminals of said reception section is detected by each of a plurality of monitoring sections disposed in said reception section, it is judged whether or not a connection state between each of the output terminals of said plurality of transmission sections and each of the plurality of input terminals of said reception station is normal, based on the detection result in each of said monitoring sections, and when the connection state is not normal, the power of the light output from the pertinent transmission section is attenuated to a predetermined level, said optical output power automatic attenuation circuit comprising, for each of said plurality of transmission sections: an identification information generating section that generates identification information whose pattern is different for each of said transmission sections; an identification information superposing section that superposes the identification information generated in said identification information generating section on the output light; an identification information comparing section that receives an electric signal indicating the detection result in said monitoring section of the power of the light input to the pertinent optical input terminal of said reception section, and compares the identification information contained in said electric signal with the identification information generated in said identification information generating section to detect whether or not they are coincident with each other; and an output power control section that attenuates the power of the output light to the predetermined level when the anticoincidence is detected in said identification information comparing section and then, returns the output light to the previously set power when the coincidence is detected in said identification information comparing section.