| 摘要 |
PROBLEM TO BE SOLVED: To improve the coupling efficiency of an optical coupler for multiplexing signal light and exciting light and to enhance its amplification rate in order to amplify the signal light and exciting light by an erbium-doped fiber. SOLUTION: A signal light side lens 14 is arranged apart a prescribed spacing in front of an optical waveguide 13 for the signal light to propagate the signal light with a single mode to constitute a signal light side collimator 15. An output side lens 17 is arranged apart a prescribed spacing in front of an optical waveguide 18 for output for propagating the signal light and the exciting light with the single mode to constitute an output side collimator 19. The signal light side collimator 15 and the output side collimator 19 are coupled at a prescribed distance via an optical multiplexing element 16. The exciting light side collimator 22 and the output side collimator 19 are coupled at the prescribed distance via this optical multiplexing element 16. The signal light and the exciting light are multiplexed and outputted by spacing coupling of the exciting light without using the optical waveguide or using the optimized lens, etc. |
