| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical directional coupler independent of polarization using, as a waveguide mode, only a super mode having even-symmetric distribution of electric field. ! SOLUTION: An optical directional coupler 200 comprises a board 101, core layers 102, 103, 104 layered on the board 101, and two ridge waveguides 201, 202 provided on the core layer 104, wherein the two ridge waveguides 201, 202 are placed close to each other so as to form a super mode having odd-symmetric distribution of electric field and a super mode having even-symmetric distribution of electric field, the effective refractive index of the super mode having the odd-symmetric distribution of electric field is smaller than or equal to the effective refractive indexes of the board 101 and ridge waveguides 201, 202 whichever is higher, the effective refractive index of the super mode having the even-symmetric distribution of electric field is larger than the effective refractive index that is higher. ! COPYRIGHT: (C |
