Patent ID: 7684655

Claim:
An electro-optic device, comprising: a semiconductor layer having a ridge extending upwards from slab regions positioned on opposing sides of the ridge, the semiconductor region having a lower ridge region positioned under the ridge and between the slab regions, the ridge defining a portion of a waveguide configured to guide light though the semiconductor layer; a modulator across the waveguide, the modulator including doped regions of the semiconductor layer, the doped regions being on opposing sides of the ridge; a lower confinement structure for charge carriers, the lower confinement structure being beneath the waveguide; lateral confinement structures for charge carriers, the lateral confinement structures being on opposing sides of the ridge, at least one of the doped regions serving as one of the lateral confinement structures; and recesses that each extends into an upper surface of one of the slab regions such that each recess is positioned between the lower ridge region and a portion of the slab region into which the recess extends, each recess extending only part way into the semiconductor layer, the recesses being on opposing sides of the ridge, each of the doped region extending from a bottom of one of the recesses down to the lower confinement structure.