| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress damage on an apparatus based on an unintended oscillation, by stopping excitation of fiber optical amplifiers from the downstream side in a laser device including multiple stages of fiber optical amplifiers. <P>SOLUTION: The laser device comprises a signal light output unit 10 which outputs signal light, and an amplification unit 20 having a plurality of fiber optical amplifiers 21-23 and outputting signal light sequentially while amplifying. The fiber optical amplifiers 21-23 each include a fiber for amplification (index a), a pumping light source (index b), and a fiber for transmission (index c) which transmits the pumping light generated from the pumping light source to the fiber for amplification. When the length of the fibers for transmission in respective stages are L<SB POS="POST">1</SB>, L<SB POS="POST">2</SB>, L<SB POS="POST">3</SB>from the upstream side, the fiber optical amplifiers 21-23 are configured to satisfy a relation L<SB POS="POST">1</SB>>L<SB POS="POST">2</SB>>L<SB POS="POST">3</SB>. <P>COPYRIGHT: (C)2013,JPO&INPIT |
