PURPOSE: To minimize the coupling loss between a laser and an optical fiber by using a piezoelectric actuator and controlling the relative positions of the laser and the optical fiber.

CONSTITUTION: A fiber gripper 45 is controlled by a piezoelectric actuator 53. A D/A converter 51 sends information to an HV amplifier 55 connected to the piezoelectric actuator 53. A control program monitors four input signals arriving through an A/D converter port. The absolute position of a piezoelectric position controller as a control signal is sent from a computer to a high voltage amplifier/piezo-controller 55 through a D/A port and combined to the actuator. The piezo-controller performs proportional-plus-integral control using a feedback position signal from a strain gauge displacement sensor installed in the actuator.