Electro-optic devices having engineered electrodes

A subassembly, comprising:

• an optical modulator, the optical modulator including a waveguide, an electrode, and an additional electrode on a substrate structure including a substrate, the waveguide including at least a portion of at least one optical material having an electro-optic effect and including lithium, the waveguide being configured to carry an optical signal, the electrode including a channel region and plurality of extensions, the plurality of extensions residing between the channel region and the waveguide, the plurality of extensions being closer to a portion of the waveguide than the channel region is and being configured to increase an electric field proximate to the waveguide for modulating the optical signal via the electro-optic effect, the electrode for carrying an electrode signal that modulates the optical signal in the waveguide in a frequency window, wherein the waveguide has a waveguide loss for the optical signal being modulated using the electrode signal of not more than 1 dB/cm and wherein the electrode has a frequency dependent electrode loss for the frequency window in a frequency range from DC to not more than five hundred GHz, the frequency dependent electrode loss being less than 0.8 dB per square root of an electrode signal frequency per centimeter, the electrode signal frequency being measured in GHz, the frequency window being at least 10 GHz, the additional electrode having an additional channel region and an additional plurality of extensions protruding from the additional channel region;
• and
• wherein at least one of the subassembly includes a driver coupled to the optical modulator and configured to electrically drive the electrode or the electrode signal is provided to the optical modulator by an electrical data signal for the optical modulator;
• wherein at least a first extension of the plurality of extensions and at least a second extension of the additional plurality of extensions each includes a top portion and a bottom portion, a first portion of the waveguide being closer to the substrate than the top portion, the bottom portion being closer to the substrate than a second portion of the waveguide is;
• wherein the first extension and the second extension configure a portion of the electric field between the first extension and the second extension for the waveguide having a particular cut of the at least one optical material.

A method, comprising:

• providing a waveguide on a substrate structure including a substrate, the waveguide including at least one optical material having an electro-optic effect, the at least one optical material including lithium, the waveguide being configured to carry an optical signal;
• and
• providing an electrode and an additional electrode, the providing the electrode and the additional electrode including:
• providing a channel region for the electrode and an additional channel region for the additional electrode;
• and
• providing a plurality of extensions protruding from the channel region and an additional plurality of extensions protruding from the additional channel region, the plurality of extensions being closer to a portion of the waveguide than the channel region is, the electrode carrying an electrode signal that modulates the optical signal in the waveguide in a frequency window, the plurality of extensions being configured to increase an electric field proximate to the waveguide for modulating the optical signal via the electro-optic effect;
• wherein the waveguide has a waveguide loss for the optical signal modulated using the electrode signal of not more than 1 dB/cm and wherein the electrode has a frequency dependent electrode loss for the frequency window in a frequency range from DC to not more than five hundred GHz, the frequency dependent electrode loss being less than 0.8 dB per square root of an electrode signal frequency per centimeter, the electrode signal frequency being measured in GHz, the frequency window being at least 10 GHz;
• wherein at least a first extension of the plurality of extensions and at least a second extension of the additional plurality of extensions each includes a top portion and a bottom portion, a first portion of the waveguide being closer to the substrate than the top portion, the bottom portion being closer to the substrate than a second portion of the waveguide is;
• wherein the first extension and the second extension configure a portion of the electric field between the first extension and the second extension for the waveguide having a particular cut of the at least one optical material.