Patent ID: 7764850

Claim:
An optical modulator, comprising: a waveguide for guiding an optical signal; a ring resonator disposed in evanescent communication with said waveguide for at least one predetermined wavelength of the optical signal; and a semiconductor pnpn junction structure at least partially coextensive with at least a portion of a resonant light path of said ring resonator, said optical modulator being configured such that said semiconductor pnpn junction structure receives an electrical control signal thereacross, the electrical control signal controlling a free carrier population in said resonant light path where coextensive with said pnpn junction structure to control a resonance condition of said ring resonator at said predetermined wavelength, said optical signal being thereby modulated according to said electrical control signal, wherein said semiconductor pnpn junction structure comprises: a first layer comprising a relatively heavily p-doped semiconductor material; a second layer adjacent to said first layer and comprising a relatively lightly n-doped semiconductor material; a third layer adjacent to said second layer and comprising a relatively lightly p-doped semiconductor material; and a fourth layer adjacent to said third layer and comprising a relatively heavily n-doped semiconductor material; wherein said resonant light path passes through at least one of said second and third layers.