| 摘要 |
PROBLEM TO BE SOLVED: To obtain an element with which an optical signal can be delayed with a small installation space and the functions of various optically functional materials can be effectively exhibited by utilizing the delay and refractive index control, by setting the wavelength of light corresponding to the end of a photonic band to the neighborhood of the wavelength of light to be transmitted. SOLUTION: The element has a structure in which materials different in refractive index (or dielectric constant) are periodically arranged so that the photonic band is formed and the wavelength of light corresponding to the end of the photonic band is set to the neighborhood of the wavelength of light to be transmitted. For example, this optical functional element has two diffraction gratings 21 which are arranged by facing each other, are formed with metallic films 22 on its surface respectively, form the phtonic band and an optically functional film 23 which is held between these diffraction gratings 21. This element is used not only as an optical delay element in optical communication but also in a case or others where plural light pulses are optically mixed by combining the group velocity thereof, and small installation space meets the requirement as well. |
