Automatic gain control device of optical fiber amplifier

摘要

An automatic gain control device of an optical fiber amplifier that outputs a compensation signal to control a gain value of the optical fiber amplifier is disclosed. The device includes: a first optical detector for partially converting an input optical signal to the optical fiber amplifier into a first electrical signal; a second optical detector for partially converting an output optical signal from the optical fiber amplifier into a second electrical signal; a first programmable amplifier having a first gain value set based on a first control signal, the first programmable amplifier inputting the first electrical signal and amplifying it at the first gain value to output a first amplified signal; a second programmable amplifier having a second gain value set based on a second control signal, the second programmable amplifier inputting the second electrical signal and amplifying it at the second gain value to output a second amplified signal; a proportional-integral derivative (PID) for outputting the compensation signal, the compensation signal corresponding to the difference between the power level of the first amplified signal and the power level of the second electrical signal; and, a controller for outputting the second control signal to the second programmable amplifier such that it has the second gain value based on a third gain value and for varying the first gain value of the first programmable amplifier until the first electrical signal and second amplified signal become the same in power level, thereby changing the gain value of the optical fiber amplifier to the third gain value.