| 摘要 |
<P>PROBLEM TO BE SOLVED: To stabilize the output level of each signal light, in an optical amplifier for amplifying wavelength multiplexed light. <P>SOLUTION: A wavelength multiplexed light is amplified by an EDF 41a and an EDF 41b. The gains of the EDF 41a and the EDF 41b are held at a constant value by an AGC (automatic gain control) circuit 43a and an AGC circuit 43b, respectively. The loss of a variable attenuator 42 provided between the EDF 41a and the EDF 41b is controlled by an ALC circuit 44 so that the output light power is held at a prescribed value. In the AGC circuit 43a, an ASE correction value predetermined is added to the detection value of an input light power obtained by a light receiving element 51a. An AGC control is made by using the input power value to which the ASE correction value is added. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
