| 摘要 |
A method of controlling a rare earth doped optical fibre amplifier 10 includes multiplexing an excitation light outputted from a first excitation light source 13 and a second excitation light source 14. The multiplexed light is divided into two excitation light beams , which are supplied to a first end region and a second end region of a fibre 22. This may be achieved by using optical fibre F5 and F6. The level of light outputted from the fibre 22 is detected. The first light source and the second light source are controlled so that the level of the light detected tends to a stationary value. The first light source and the second light source are controlled in a state selected from among (a) a first state in which currents supplied to the first excitation light source and the second light excitation light source are set to predetermined amounts respectively, (b) a second state in which a current supplied to the first excitation light source is set to twice its predetermined amount and a current supplied to the second excitation light source is set to zero, and c) a third state in which current supplied to the first excitation light is set to zero and a current supplied to the second excitation light source is set to twice the predetermined amount. |
