| 摘要 |
A current (Ii) supplied to an excitation light source (20) is detected, and time-averaged by a predetermined time-constant to calculate a time-average current (Iav). An output optical power (Pi) which is output from an amplification-use optical fiber (12) is detected, which is time-averaged by the predetermined time-constant to calculate a time-average output optical power (Pav). Using a reference output optical power (Pr) and a reference current (Ir) which is supplied to the excitation light source (20) when the reference output optical power (Pr) is output from a fiber laser device (1), an output optical power expected value Pex = Iav × Pr / Ir is calculated, the time-average output optical power (Pav) and the output optical power expected value (Pex) are compared, and on the basis of the comparison results, decrease in output optical power of the fiber laser device (1) is assessed. |
