| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent an SHG crystal from being broken owing to a surge generated by a fiber laser during a rise when an excitation semiconductor laser, a fiber laser, and an SHG laser comprising the SHG crystal (light wavelength conversion element) are pulse-driven. Ž<P>SOLUTION: At a leading edge of a PWM signal driving the SHG laser 2, a gradient is given to a rise in a section of signal level corresponding to an approximate value at which a semiconductor laser 21 starts emitting light, and the value of the gradient is made adjustable by a rise control means 6. The raise control means 6 is operative to receive an optical output of an optical output detecting means 3, to generates the gradient value which increases at a constant ratio for a constant period by an adjustment signal generating means 5 when a surge detecting means 4 detects no surge, and to output a gradient value right before surface detection once a surge is detected. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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