JPH05347446

PURPOSE:To output a laser for excitation having power higher than the rating of a laser diode from the laser diode. CONSTITUTION:Two or more of laser diodes 1 are controlled by a pulse driver circuit 2, laser beams A, B for excitation are emitted alternately from each laser diode 1, and the laser beams A, B for excitation are synthesized and fed to an optical fiber amplifier 3. Consequently, the power consumption of the driver circuit for the laser diodes can be lowered. Since switching distortion due to pulse driving is offset, light to be amplified is not subject to the effect of the offset. Since noises due to switching are absorbed to a laser for excitation by the characteristics of an erbium-doped fiber, amplified light is not subject to the effect of the noises.