| 摘要 |
<p>A modulator (1) for modulating an optical signal (2) is disclosed having a substrate (10), a support (12) mounted to the substrate (10), and membrane (15) attached to the support (12) and defining an airgap (20) between the substrate (10) and the membrane (15). The membrane (15) has at least three layers (15a-15c) including a central layer (15b) having an index of refraction which is the square root of the index of refraction of the substrate. The thickness of the layers (15a-15c) and the size of the airgap (20) are optimized to maximize differential reflectivity of light (2) incident on the membrane (15) at a non-normal angle of incidence to the membrane (15) when the membrane (15) is either in an unbiased state or biased state. In one embodiment, the first, central, and third layers (15a-15c) have corresponding thicknesses approximately equal to one-quarter, one-quarter, and on-half of a wavelength of the optical signal (2) , respectively. In another embodiment, the thickness of the layers (15a-15c) and the airgap (20) are designed according to formulas such that the modulator (1) can operate over wider angles of incidence up to about 55 degrees. In a third embodiment, the modulator (1) can operate at an angle of incidence up to about 85 degree with TE-only polarization of the incident light (2). (Figure 1)</p> |
