| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical amplifier for compensating the influence of the natural discharged light, which becomes the main cause of errors at the time of constantly controlling the gain, by including the variations of the natural discharged light intensity due to non-uniformity in the rare earth doped fiber. <P>SOLUTION: In a gain error compensation circuit 7, a sum of an ASE electric signal level Pase_homo included in an output photoelectric signal level Pout and an electric signal level ΔPase_inhomo corresponding to an ASE intensity variation is previously set as the gain compensation level ΔG, and the circuit generates an output an electric signal correction level Pout' obtained by subtracting the gain compensation level ΔG from the output photoelectric signal level Pout. A gain constant control circuit 8 controls an excitation light source 4 so that a level ratio of the output photoelectric signal correction level Pout' generated from the gain error compensation circuit 7, and an input photoelectric signal level Pin always becomes a constant ratio G. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
