Pumping method and unit for optical amplifiers

An optical coupling section, for coupling a signal radiation at wavelength λs, a first pump radiation at wavelength λp1 and a second pump radiation at wavelength λp2, comprising

• a first and a second port for receiving respectively the first and the second pump radiation;
• a third port for the signal radiation;
• and
• a fourth port,
• and being adapted to combine the signal radiation and the first and second pump radiation in the fourth port through a reversal of the direction of propagation of the first pump radiation from the first port to the fourth port.

Method for coupling a first radiation at wavelength λp1, a second radiation at wavelength λp2 and a third radiation at wavelength λs through a common coupling section having a first and a second side that are opposed to one another, the first side comprising a first and a fourth port and the second side comprising a second and a third port, said method comprising the steps of

• a) propagating the second radiation from the second port to the first port;
• b) deviating the path of the second radiation so as to send it to the fourth port;
• c) sending the third signal radiation from the third port to the fourth port, or vice versa, from the fourth port to the third port;
• d) propagating the first radiation from the first port to the second port;
• and
• e) reversing the direction of propagation of the first radiation to send it to the fourth port.