OPTICAL AMPLIFIER MEDIUM CONTROL METHOD, OPTICAL AMPLIFIER DEVICE AND SYSTEM USING THE SAME

摘要

PROBLEM TO BE SOLVED: To suppress the occurrence of optical serge and to realize amplification without deteriorating the S/N ratio of signal light output with simple constitution by controlling an optical amplifier device to possess a maximum gain at the prescribed value of signal light input intensity and to possess a positive gain area which is not more than the maximum gain against signal light input intensity which is not more than the prescribed value. SOLUTION: An optical amplifier medium is controlled so that the gain of signal light intensity inputted to the optical amplifier medium has the maximum gain at the prescribed value of input signal intensity and it has the gain of not more than the maximum gain against the decided input intensity range or not more than the prescribed value. When signal light becomes less than a regulated range, excessive accumulation energy is kept in the optical amplifier medium when the gain amplification rate of the optical amplifier medium is maintained in the similar way as a regular operation, and it becomes the cause of the occurrence of optical serge. The signal light gain tends to finely increase (dotted line in drawing) as input signal light intensity deteriorates. When the signal light gain is deteriorated, the occurrence of optical serge can be prevented.