| 摘要 |
A multi-mode optical fiber segment having partially reflecting mirrors on each end functions as a resonant cavity with respect to the modulation frequency when the length of the fiber is equal to one-half the modulation wavelength of the light injected into the fiber. Modulated light is injected through a hole in the mirror at one end, either from a fiber, a waveguide, or directly from a laser diode. The core diameter of the cavity fiber is limited only by the requirement that it must be much larger than the input hole. Light exits though a hole in the mirror opposite the input hole. Upon entry into the resonant cavity, light is subject to multi-modal propagation resulting in dispersion. The resultant output light of the fiber is lower overall in intensity, but its useful frequency response is expanded by the bandpass half-skirt of the fiber-optic filter.
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