Patent ID: 9025240
Filing Date: 2015-05-05
Classification: B23K,H01S

Abstract:
1. A light amplifier comprising: a light amplifying fiber that amplifies seed light by exciting light; a seed light source that generates the seed light a plurality of times during an emission period as a group of pulses including a plurality of pulses; an excitation light source that generates the exciting light of a power at a first level during a non-emission period which is immediately before the emission period and generates the exciting light of a power at a second level which is greater than that of the first level during the emission period; a detector that detects power of a group of output light pulses which is output from the light amplifying fiber; and a controller that controls the power of the exciting light of the non-emission period based on a detected value from the detector to control the power of the group of output light pulses, wherein the detector comprises a light receiving element that receives the group of output light pulses, an integration circuit that integrates an output signal from the light receiving element, and an analog-to-digital (A/D) converter circuit that generates the detected value based on the output signal from the integration circuit.