| 摘要 |
PURPOSE:To enable collimate-positioning accurately while the semiconductor laser is driven by an APC circuit by a method wherein the APC circuit is combined with a chopper. CONSTITUTION:When a return light is turned ON-OFF by the chopper 12 by setting the value of the monitor photocurrent of the APC circuit at the value corresponding to a phot output P0, the drive current reciprocates between the current value (a) of the photo output P0 in the presence of return light and the current value (b) of the photo output P0 in the absence of return light. The photo output monitor current or the semiconductor laser drive current of an APC power source 11 should be the input signal to a peak-to-peak detection circuit 13. When this circuit 13 finds out the maximum value of the amplitude of the input signal by moving a semiconductor laser package 10 in the direction of the optical axis of a collimating lens 2 with a moving means 9, the collimate-positioning of the semiconductor laser can be carried out by the stop of the moving means 9 by a movement control circuit 8. |
