Double analog/digital automatic power controlling device in optical fiber amplifier

Abstract From the Canadian patent

There is provided a device for automatically the output of a pump laser diode used as an excitation light source in an erbium doped fiber amplifier (EDFA). The automatic power controlling device can stabilize an optical signal output via a final output terminal in an optical fiber amplifier by selecting a first feedback control loop using an output photodiode or a second feedback control loop using a photodiode provided in a pump laser diode and controlling an optical excitationsignal output from the pump laser diode on the basis of the intensity of an output optical signal detected through the selected feedback control loop in an analog or digital double automatic controlling method.