US 6,845,198 B2 · High-speed silicon-based electro-optic modulator

Abstract

A silicon-based electro-optic modulator is based on forming a gate region of a first conductivity to partially overly a body region of a second conductivity type, with a relatively thin dielectric layer interposed between the contiguous portions of the gate and body regions. The modulator may be formed on an SOI platform, with the body region formed in the relatively thin silicon surface layer of the SOI structure and the gate region formed of a relatively thin silicon layer overlying the SOI structure. The doping in the gate and body regions is controlled to form lightly doped regions above and below the dielectric, thus defining the active region of the device. Advantageously, the optical electric field essentially coincides with the free carrier concentration area in this active device region. The application of a modulation signal thus causes the simultaneous accumulation, depletion or inversion of free carriers on both sides of the dielectric at the same time, resulting in high speed operation.

Claims134

Dependent claims

A silicon-based electro-optic device comprising:

a relatively thin silicon body region doped to exhibit a first conductivity type;
a relatively thin silicon gate region doped to exhibit a second conductivity type, the silicon gate region disposed at least in part over the silicon body region to define a contiguous area between said silicon body and gate regions;
a relatively thin dielectric layer disposed in the contiguous area between said silicon body and gate regions, the combination of said silicon body and gate regions with the interposed relatively thin dielectric layer defining the active region of the electro-optic device;
a first electrical contact coupled to said silicon gate region;
and
a second electrical contact coupled to said silicon body region, wherein upon application of an electrical signal to the first and second electrical contacts, free carriers accumulate, deplete or invert within the silicon body and gate regions on both sides of the relatively thin dielectric layer at the same time, such that the optical electric field of said optical signal substantially overlaps with the free carrier concentration modulation area in the active region of said electro-optic device.

3 more elements

A Mach-Zehnder interferometer comprising

an input optical waveguide splitter, defined as comprising an input waveguide section optically coupled to both a first arm and a second arm, said first and second arms disposed in parallel;
and
an output optical waveguide combiner, defined as comprising an output waveguide section optically coupled to the input optical waveguide splitter first and second arms, wherein the first arm includes a first electro-optic phase modulator comprising:
a relatively thin silicon body region doped to exhibit a first conductivity type;
a relatively thin silicon gate region doped to exhibit a second conductivity type, the silicon gate region disposed at least in part over the silicon body region to define a contiguous area between said silicon body and gate regions;
a relatively thin dielectric layer disposed in the contiguous area between said silicon body and gate regions, the combination of said silicon body and gate regions with the interposed relatively thin dielectric layer defining the active region of the electro-optic device;
a first electrical contact coupled to said silicon gate region;
and
a second electrical contact coupled to said silicon body region, wherein upon application of an electrical signal to the first and second electrical contacts, free carriers accumulate, deplete or invert within the silicon body and gate regions on both sides of the relatively thin dielectric layer at the same time, such that the optical electric field of said optical signal substantially overlaps with the free carrier concentration modulation area in the active region of said first electro-optic phase modulator device.

6 more elements

Dependencies are inferred from the claim text.

High-speed silicon-based electro-optic modulator

Life of this patent

High-speed silicon-based electro-optic modulator

Life of this patent

Abstract

Claims134