Patent ID: 6580553
Filing Date: 2003-06-17
Classification: H01S

Abstract:
An automatic gain control device of an optical fiber amplifier which outputs a compensation signal to control a gain value of the optical fiber amplifier, said device comprising:a first optical detector for partially converting an input optical signal to said optical fiber amplifier into a first electrical signal; a second optical detector for partially converting an output optical signal from said optical fiber amplifier into a second electrical signal; a first programmable amplifier having a first gain value set based on a first control signal, said first programmable amplifier amplifying said first electrical signal at said 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, said second programmable amplifier amplifying said second electrical signal at said second gain value to output a second amplified signal; a proportional-integral derivative (PID) for outputting said compensation signal, corresponding to a difference between the power level of said first amplified signal and the power level of said second electrical signal; and, a controller for outputting said second control signal to said second programmable amplifier to set said second gain value to a third gain value and for varying said first gain value of said first programmable amplifier until said first electrical signal and second amplified signal become the same in power level, so that the gain value of said optical fiber amplifier changes to said third gain value.