| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical branching element with less intensity dispersion between branched beams each other and with large diffraction efficiency. SOLUTION: A beam propagating through an optical fiber 10 is emitted from the end surface 10a of the optical fiber 10, and is made parallel beams by a lens 20, and is inputted to a diffraction grating 30, is diffracted by the diffraction grating 30. Respective diffracted beams diffracted by the diffraction grating 30 are made incident on respective end surfaces 51a-53a of the optical fibers 51-53 by the lens 40 to be propagated respectively through the optical fibers 51-53. The diffraction grating 30 that a change of its thickness imparting a phase difference to the beam transmitting through is distributed two- dimensionally diffracts the inputted beam to branch it to plural diffracted beams going in the directions different from each other on the same plane each other. |
