| 摘要 |
PURPOSE: To reduce a manufacturing cost by measuring a variation ratio of a monitor signal for a drive signal supplied to a device, and deciding monitor sensitivity based on differential efficiency of a variation ratio and a device. CONSTITUTION: A correction routine is performed, a controller 44 makes a feedback loop 42 of a device side non-operation by a signal ENS, sets temporarily a monitor sensitivity value SENS to '1', and sets gain of a scale circuit 54 to '1'. Thereby, a laser output level is adjusted by a monitor standard level signal MREF generated by the controller 44. Successively, the signal MREF is set to a first monitor standard level, and a drive signal DRI indicating a drive level IL is stored in the controller 44. Successively, a second monitor standard level is outputted, and the signal DRI is stored. And monitor sensitivity is calculated by the prescribed operation using differential efficiency of these values and a laser. Therefore, monitor sensitivity is automatically decided, and the manufacturing cost can be reduced. |
