| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device capable of achieving optical coupling with independently determined diffraction efficiency and coupling efficiency of signal light having a propagation direction altered (diffracted) by a grating.SOLUTION: An optical device includes a first layer 21 constituting one end of an optical waveguide, and optical diffraction means which includes a second layer 22 formed on the first layer 21 and having lower refractive index than that of the first layer 21 and which diffracts light entering the second layer 22 from the first layer 21 and allows the diffracted light to exit from the second layer 22 to the first layer 21. In one embodiment of the optical device, the optical diffraction means has a third layer 23 having a diffraction grating structure formed on the second layer. In another embodiment of the optical device, the second layer 22 has a diffraction grating structure. |
