| 摘要 |
A fiber-optic bandpass filter comprising a resonant cavity formed in an optical waveguide is coupled to a fiber-optic bus which carries a large number of frequency multiplexed channels. The fiber-optic bandpass filter is selected to be one-half the modulation wavelength of the desired center frequency within a range of frequencies carried on the same transmission. The creation of a resonant cavity at the desired center frequency provides a filter which reduces the intensity of signals at surrounding frequencies so that an overall reduced output power is provided, resulting in less cross-talk between a large number of frequency multiplexed signals which, unfiltered, would all have equal power. The filter is broad enough that many adjacent channels are not significantly attenuated. The optical waveguide of which the filter is formed may be in the form of an optical fiber segment or a planar waveguide.
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