| 摘要 |
PROBLEM TO BE SOLVED: To suppress power change before the change of the electric power reaches a sensing element, to improve the system performance and to decrease the power margin by judging the possible change of the optical electric power and reducing the above described electric power. SOLUTION: A phade-in.phade-out control means 6 performs the supply to an electric-power setting-value controller 5 arranged in the respective light source. The means 6 is operated so that the preset value is changed for the output of one light source in correspondence with a change judging means 7 for outer stimulus. This outer stimulus has the instruction form, which, for example, one switch of the light sources is turned off for maintenance and reconstitution. In this case, by turning off the switch suddenly, the total optical electric power is sufficiently changed, and the disturbance is applied to the optical amplifier. Thus, hit errors are caused. Therefore, one or both of the light sources are controlled, and a microcontroller gradually decreases the output electric power of the suitable light source. |
