Method for controlling an erbium doped fiber amplifier (edfa) and amplifier arrangement

A method for controlling an optical fiber amplifier with a first amplifier stage and a second amplifier stage, pumped by a single pump light source generating a primary pump signal, the method which comprises:

• splitting the primary pump signal in a tunable splitter into a first pump signal and a second pump signal according to a splitting factor, for pumping the first amplifier stage and the second amplifier stage, respectively;
• determining a primary actuating variable for controlling a second pump power of the second pump signal and therefore an output power of the amplifier;
• adjusting a total pump power of the primary pump signal according to the primary actuating variable while maintaining a maximum splitting factor if the total pump power of the primary pump signal is less than an available maximum total pump power of the primary pump signal;
• and
• adjusting the splitting factor of the tuneable splitter according to the primary actuating variable if the total pump power equals the maximum total pump power of the primary pump signal.

An optical amplifier, comprising:

• a single pump light source for generating a primary pump signal;
• a tuneable splitter having a variable splitting factor for dividing the primary pump signal into a first pump signal and a second pump signal;
• a first amplifier stage and a second amplifier stage connected to receive the first pump signal and the second pump signal, respectively;
• and
• a control unit for monitoring an output power of the amplifier and for controlling the primary pump signal, said control unit being configured to:
• determine a primary actuating variable for controlling a second pump power of the second pump signal and therefore the output power of the amplifier;
• adjust a total pump power of the primary pump signal according to the primary actuating variable while maintaining a maximum splitting factor if a total pump power of the primary pump signal is less than a maximum total pump power of the primary pump signal;
• and
• adjust the splitting factor of said tuneable splitter according to the primary actuating variable if the total pump power equals the maximum total pump power of the primary pump signal.