| 摘要 |
PROBLEM TO BE SOLVED: To provide a wide-band optical modulator that is small in size, low in drive voltage, and less in light absorption loss.SOLUTION: An optical modulator 10 comprises: a monocrystal substrate 4 whose dielectric constant is 17 or below; an electric optical film 5, formed on the monocrystal substrate 4, whose optical refractive index is nc and whose film thickness is 2 μm or less; and a buffer layer 6, formed between the electric optical film 5 and a progressive wave electrode 8, whose dielectric constant is &egr;b and optical refractive index is nb. The optical modulator satisfies (nc-nb)&egr;b>3.5. |
