A silicon-based electro-optic modulator includes a substrate layer, an insulation layer, and an optical waveguide layer stacked sequentially, traveling wave electrodes disposed above the optical waveguide layer, and a metal grating structure periodically configured along the direction in which an electrical signal propagates in the traveling wave electrodes. The metal grating structure is disposed above the optical waveguide layer.

An electrical-optical modulator may include one or more optical waveguides to propagate one or more optical signals in a direction of propagation. An optical waveguide of the one or more optical waveguides may include a time delay section, a first modulation section preceding the time delay section in the direction of propagation, and a second modulation section following the time delay section in the direction of propagation. The first modulation section and the second modulation section may be configured to be associated with opposite modulation polarities, and the time delay section may be configured to delay a phase of the one more optical signals relative to the first modulation section. The electrical-optical modulator may include one or more signal electrodes to propagate one or more signals in the direction of propagation in order to modulate the one or more optical signals through electrical-optical interaction.

An electrical-optical modulator may include a first section configured for a first electrical-optical interaction between one or more optical waveguides and one or more signal electrodes. The electrical-optical modulator may include a second section configured to increase or decrease a relative velocity of signals of the one or more signal electrodes to optical signals of the one or more optical waveguides relative to the first section. The electrical-optical modulator may include a third section configured for a second electrical-optical interaction between the one or more optical waveguides and the one or more signal electrodes according to an opposite modulation polarity relative to the first section.

Structures for an optical power modulator and methods of fabricating a structure for an optical power modulator. A first waveguide core includes first and second sections. A second waveguide core includes a first section laterally adjacent to the first section of the first waveguide core and a second section laterally adjacent to the second section of the first waveguide core. An interconnect structure is formed over the first waveguide core and the second waveguide core. The interconnect structure includes first and second transmission lines. The first transmission line is physically connected within the interconnect structure to the first section of the first waveguide core. The second transmission line includes a first section physically connected within the interconnect structure to the second section of the first waveguide core and a second section adjacent to the first transmission line.

A semiconductor optical modulator includes a modulation region and a non-modulation region. A first width of a first ground electrode in the non-modulation region is larger than a second width of the first ground electrode in the modulation region. A third width of a second ground electrode in the non-modulation region is larger than a fourth width of the second ground electrode in the modulation region. In the non-modulation region, a first insulating layer is disposed between a first optical waveguide and a first traveling wave electrode and between a second optical waveguide and a second traveling wave electrode. For this reason, a bandwidth of the semiconductor optical modulator can be widened.

An optical phase modulator comprises a cascaded array of optical resonators, wherein each of the optical resonators has an input port and an output port. A plurality of waveguides are coupled between the optical resonators and are configured to provide cascaded optical communication between the optical resonators. Each of the waveguides is respectively coupled between the output port of one optical resonator and the input port of an adjacent optical resonator. A transmission electrode is positioned adjacent to the optical resonators, with the transmission electrode configured to apply a drive voltage across the optical resonators. The optical phase modulator is operative to co-propagate an input optical wave with the drive voltage, such that a resonator-to-resonator optical delay is matched with a resonator-to-resonator electrical delay.

A velocity mismatch between optical signals and microwave electrical signals in electro-optic devices, such as modulators, may be compensated by utilizing different lengths of bends in the optical waveguides as compared to the microwave electrodes to match the velocity of the microwave signal propagating along the coplanar waveguide to the velocity of the optical signal. To ensure the electrode bends do not affect the light in the optical waveguide bends, the electrode may have to be rerouted, e.g. above or below, the optical waveguide layer. To ensure that the pair of optical waveguides have the same optical length, a waveguide crossing may be used to cross the first waveguide through the second waveguide.

An optical modulator includes an optical waveguide, a first slab and a second slab. The optical waveguide is formed by filling polymer in a slot portion formed between a first rail and a second rail disposed in parallel to the first rail. The first slab includes a first partial slab electrically connected to a first electrode and a second partial slab that electrically connects the first rail and the first partial slab. In the first slab, a thickness dimension of the second partial slab is set small compared with that of the first rail. The second slab includes a third partial slab electrically connected to a second electrode and a fourth partial slab that electrically connects the second rail and the third partial slab. In the second slab, a thickness dimension of the fourth partial slab is set small compared with that of the second rail.

A optical modulator with reduced with a reduced amount of ripple is provided. A Mach-Zehnder optical modulator includes a phase modulation unit including optical waveguides having a PN junction structure and traveling wave electrodes, and a dummy phase modulation unit including portions of the traveling wave electrodes, the portions being obtained by forming the respective traveling wave electrodes longer than the phase modulation unit in the light propagation direction of the phase modulation unit, and optical waveguides having the same PN junction structure as that of the optical waveguides of the phase modulation unit and not connected to the optical waveguides of the phase modulation unit.

A method of fabricating an electro-optical device is provided. The method comprises providing a silicon-on-insulator (SOI) wafer comprising a silicon layer, a silicon oxide layer and at least one RF (radio frequency) electrode, wherein the at least one RF electrode is arranged inside the upper portion of the silicon oxide layer of the SOI wafer and providing a second substrate having a top structure of a RF (radio frequency) modulating material. The method further comprises bonding the second substrate on top of the SOI wafer such that said top structure of a RF (radio frequency) modulating material is arranged over the at least one RF electrode. Also, an electro-optical device is provided.