| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance the detection accuracy of a laser beam amount, by improving the output linearity of a laser power monitor with respect to high-output laser emission power. <P>SOLUTION: The laser power monitor 10 for photoelectrically converting a laser beam LB from a semiconductor laser 2 to generate and output a monitor signal for feedback control includes, on a beam-receiving surface LS, a center beam receiving part A near an optical axis a and its surrounding annular beam-receiving part B. A feedback control unit 11 for generating and outputting a feedback control signal Sf for a semiconductor laser is provided with a first amplifier Am1 for a monitor signal Sm1 from the center beam receiving part, a second amplifier Am2 for a monitor signal Sm2 from the annular beam receiving part, and an addition output part 11a for adding the output signals of the first and second amplifiers and outputting the result. The gain of the second amplifier is set higher than that of the first amplifier. <P>COPYRIGHT: (C)2008,JPO&INPIT |
