PURPOSE: To shorten a loss time to a follow-up start immediately after moving by moving an actuator to a position corresponding to the maximum value of a laser optical output at the time of generating a reset signal.
CONSTITUTION: A set potential obtained from a reset voltage setter 18 is selected to +K or -K, and supplied to an integrator 11 through a resistor 19. Actuators 7, 8 always follow up a vertex of a crest (e). When an integrated output S becomes, for example, an upper limit value by the follow-up state, a reset signal is output at 17 according to a trigger signal from a comparator 16, and a switch 12 is closed. Further, the comparator 16 outputs a positive + signal indicating a high potential side of a comparison output, the setter 18 outputs a potential -K, and the integrator 11 is charged. Here, the voltage K is selected to a value corresponding to one wavelength of a driving voltage V, and the actuators 7, 8 are retracted by one wavelength, and forcibly moved to a position corresponding to a vertex of the crest (f) before one crest. Accordingly, a loss time to a follow-up start to the vertex of the crest (f) immediately after moving to the crest (f) can be shortened.
OKIKURA HARUHIKO
ISHIDA TOSHIO
SUZUKI KAZUO
JAPAN AVIATION ELECTRON
| JP2500627Y |