| 摘要 |
PURPOSE: To simplify a setting work by adjusting a laser beam output to a fixed value and also making an adjusting signal for adjusting the laser beam to be inputted to a second input side of a multiplier. CONSTITUTION: An optical output of laser 1 is adjusted to a constant value, and also an adjustment signal LS is supplied to a second input side of multiplier 8 to adjust the laser 1. And the optical output of the laser 1 is adjusted to a constant value by using a regulator 6, because the regulator 6 responds to the laser current at a higher speed compared with the frequency of periodic signal PS. Namely, the regulator 6 regulates by laser current variations and the optical output variations of the laser 1 caused by periodic signal SP. Thus, setting work to the laser and convergence detector is remarkably simplified. |
