Patent ID: 9703125
Date: 2017-07-11
CPC Classifications: G02F

Claim:
1. A silicon-based electro-optic modulator having an SIS (semiconductor-insulator-semiconductor) junction in which a first silicon semiconductor layer doped to exhibit a first type of conductivity and a second semiconductor layer doped to exhibit a second type of conductivity are at least partly stacked together, and a relatively thin dielectric is formed at the interface between the stacked first and second silicon semiconductor layers, and exploiting that the free carrier concentration felt by an optical signal electric field is modulated as a result of free carriers' being accumulated, depleted or inverted on each side of the relatively thin dielectric layer by electrical signals from electrical terminals connected with, respectively, the first and second silicon semiconductor layers, wherein: the first silicon semiconductor layer is fabricated into a rib waveguide shape comprising a rib portion, which is formed into a protruding shape and to become the core of the rib waveguide, and slab portions which are located on respective sides of the rib portion and connected with the rib portion; the silicon-based electro-optic modulator comprises a first heavily doped region formed by a high concentration doping process, in a portion of the first silicon semiconductor layer neighboring to each of the slab portions, and a second heavily doped region formed by high concentration doping into a portion of the second silicon semiconductor layer; and the first heavily doped region has almost the same height as that of the rib portion of the rib waveguide, wherein a top region of the rib portion consists of a Si