| 摘要 |
An apparatus for modulating an optical signal and a method for fabricating such an apparatus, are disclosed. The apparatus, which may be formed on a semiconductor wafer or chip, consists of a membrane that is supported over a substrate by flexible support arms. An air gap is defined between the membrane and substrate. The membrane thickness and refractive index are chosen so that the reflectivities of the membrane and substrate are not 180 DEG out of phase. Under the action of bias, the membrane moves vertically from a first position to a second position relative to the substrate, changing the air gap. The reflectivity of the modulator changes as the air gap changes. Membrane thickness and the air gap are suitably selected to achieve zero overall modulator reflectivity in one of the two membrane positions. Equations define acceptable values for the thickness of the membrane thickness and the air gap. The membrane and air gap are formed by various etching and photolithographic methods.
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