| 摘要 |
PURPOSE:To separate different signals selectively from one light guide according to wavelength, by forming periodic structures at coupling parts of the light guide at specific intervals so that the product of the strength and length of periodic coupling is >=3. CONSTITUTION:On one light guide L0, plural N units of light guides L1, L2- LN(Li) are arranged closely through plural N units of coupling parts C1, C2- CN(Ci) while shifted in position lengthwise. The light guides L0 and Li have different phase constants and between the light guides L0 and Li, N units of periodic structures F1, F2-FN(Fi) of rugged gratings are formed to obtain reverse directional coupling for plural wavelengths lambda1, lambda2-lambdaN. In this case, the product of the strength and length of the periodic coupling of the structure Fi is >=3, so a high constant coupling rate is obtained without reference to coupling length and the phase constants of the waveguides L0 and Li are different, obtaining high coupling efficiency. |
