| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical encoder and an optical decoder in which high performance optical encoding and optical decoding can be carried out with a simple constitution even though optical pulse signal having a wide pulse width is used. <P>SOLUTION: The optical encoder is provided with an optical grating waveguide where uniform pitch grating sections whose number is the same as the number of optical code chips, each of which reflects inputted optical pulse signals, and which are formed in a waveguide direction. A λ/4 phase shift section is provided between adjacent uniform pitch grating sections corresponding to the change positions of encoded values in an encoded group. A zero phase shift section is provided between other adjacent uniform pitch grating sections. Reflectivity of the uniform pitch grating sections is increased as they are separated from input / output terminals. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
