| 概要 | Multimode optical fibers can carry many messages simultaneously, each one encoded in lightwaves of different wavelength (color) but at the receiving station, the messages must be separated. For this reason we need a wavelength separator. The usual ones are very large and also the different wavelengths are not completely separated. They are designed according to the principles of geometric optics in which the wave nature of light is neglected. We took a different approach. Using coupled whispering gallery mode resonators, the size of which are on the order of the wavelength of light, we designed a wavelength separator based on the principles of vector wave optics. A typical whispering gallery mode resonator is shown below in Fig. 2. It is just a dielectric cylinder. When light of a few special wavelengths is coupled into the cylinder, the light intensity (indicated by different colors: red = strong, blue = weak) inside and outside forms a static pattern. Light of other wavelengths does not form this pattern.
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