PURPOSE: To enable production of the prescribed output laser beam driving a semiconductor laser diode at the most suitable driving current point thereof by a method wherein an attenuating means is provided in an output laser beam producing path to attenuate a transmitting beam.
CONSTITUTION: An attenuating means 102 to attenuate a transmitting beam is provided in an output laser beam producing path, and a semiconductor laser diode 101 is made to be driven at the most suitable driving current point thereof. For example, as optical fiber to construct pigtail fiber 3A, fibers having different attenuations per unit length are used, and moreover by changing length thereof, fiber having voluntarily different attenuation can be manufactured. Thereupon, by selecting fiber from preliminarily prepared pigtail fibers having various attenuations and using the fiber thereof, the desired attenuation can be bestowed. Accordingly, the prescribed output laser beam can be produced driving the semiconductor laser diode at the most suitable driving current point thereof even when the beam output characteristic of the semiconductor laser diode has dispersion.
YAKO HIROSHI
WADA TETSUO
MORI MASAKAZU
