| 摘要 |
A current Ii supplied to a pumping light source 20 is detected and time-averaged with a predetermined time constant to calculate a time-averaged current Iav. An optical output power Pi outputted from an amplifying optical fiber 12 is detected and time-averaged with the predetermined time constant to calculate a time-averaged optical output power Pav. A reference optical output power Pr and a reference current Ir supplied to the pumping light source 20 when the reference optical output power Pr is outputted from an optical fiber laser apparatus 1 are used to calculate an optical output power expectation value Pex=Iav×Pr/Ir. The time-averaged optical output power Pav and the optical output power expectation value Pex are compared with each other to determine a decrease of an optical output power of the optical amplifier apparatus 1 based on the comparison result. |
