PURPOSE: To stably control a laser power and a wavelength without confusion in control by executing a superposing control and exciting intensity control to eliminate influences of the superposing control and the exciting intensity control at different timing.
CONSTITUTION: A superposing controller 4 which receives a superposing control execution command 41 from a main CPU 1 transmits a superposing regulation signal 43 to etalons 7, 7' and returns a superposing control completion signal 44 to the CPU 1. An exciting intensity controller 3 transmits an exciting intensity regulation signal 33 to a laser power source 10, raises or lowers a discharge voltage, and then returns an exciting intensity control completion signal 34 to the CPU 1. Since next control is started after receiving the control completion signal, the cause of varying the laser power during controlling can be easily recognized, thereby preventing the controls due to competition between both the controls from confusing.
WAKABAYASHI OSAMU
KOWAKA MASAHIKO
