METHOD FOR MONITORING CHARACTERISTIC OF LIGHT AMPLIFIER AND CHARACTERISTIC MONITORING CIRCUIT OF LIGHT AMPLIFIER

摘要

PURPOSE: To monitor the characteristic of a light amplifier by measuring the input/output optical power P₁ and P₀ of a light amplifier, calculating the gain in operation by calculating the P₀/P₁, determining initial gain, obtaining the fluctuation value for the initial gain of the gain in operation and comparing the obtd. value with a fluctuation allowable value. ;CONSTITUTION: By the electric signals that first and second optic/electric conversion parts 6a and 6 output, monitor levels P₁M and P₀M are measured. Because these P₁M and P₀M are the optical levels which are partially branched from signal light, an offset value is added to each level and an input optical level P₁ and an output optical level P₀ are calculated. The operation of P₀/P₁ is executed and the gain G of a fiber type light amplifier is calculated. At this stage, the fluctuation value of the gain of the fiber type light amplifier in operation for the initial gain of of the fiber type light amplifier in operation for the initial gain of the fiber type light amplifier is calculated 8. Next, the allowable gain fluctuation value stored in a storage part 9 is read, the allowable value is compared with the gain fluctuation value obtd. before. When the gain fluctuation value is larger than the allowable value, an alarm is given.;COPYRIGHT: (C)1996,JPO