Electro-optic devices having closely spaced engineered electrodes

A subassembly, comprising:

• an optical modulator, the optical modulator including a waveguide, a first engineered electrode, and a second engineered electrode, the waveguide including lithium and having an electro-optic effect, a portion of the waveguide having a waveguide width and including a ridge waveguide, the first engineered electrode including a first channel region and a first plurality of extensions protruding from the first channel region, the second engineered electrode including a second channel region and a second plurality of extensions protruding from the second channel region, a first extension of the first plurality of extensions being a distance from a second extension of the second plurality of extensions along a direction transverse to an optical signal direction, the distance being less than the waveguide width and nonzero,
• the waveguide carrying an optical signal, the portion of the waveguide confining an optical mode of the optical signal such that the optical mode is attenuated by at least 20 dB at an attenuation distance from the portion of the waveguide, the first engineered electrode and the second engineered electrode being not closer to the portion of the waveguide than the attenuation distance, wherein at least one of the first engineered electrode and the second engineered electrode are configured to carry at least one electrode signal that generates an electric field that modulates the optical signal with a frequency dependent loss of not more than 0.8 dB per square root of an electrode signal frequency in GHz per centimeter in a frequency window of at least 10 GHz via the electro-optic effect, the frequency window in a frequency range to not more than five hundred GHz;
• and
• a driver coupled to the optical modulator and configured to electrically drive the first engineered electrode and the second engineered electrode;
• and
• wherein a functionality of the optical modulator is tailored by configuring compositions, shapes, dimensions, placements, and/or orientations of the first engineered electrode, the second engineered electrode, the first plurality of extensions, and the second plurality of extensions relative to a composition, cut, and/or cross-sectional profile of the ridge waveguide.

A method, comprising:

• providing a waveguide including at least one optical material having an electro-optic effect, the at least one optical material including lithium, a portion of the waveguide having a waveguide width and including a ridge waveguide, the waveguide being configured to carry an optical signal;
• and
• providing a first engineered electrode including:
• providing a first channel region;
• and
• providing a first plurality of extensions protruding from the first channel region;
• providing a second engineered electrode including:
• providing a second channel region;
• and
• providing a second plurality of extensions protruding from the second channel region, a first extension of the first plurality of extensions being a distance from a second extension of the second plurality of extensions along a direction transverse to an optical signal direction, the distance being less than the waveguide width and nonzero;
• wherein at least one of the first engineered electrode and the second engineered electrode are configured to carry at least one electrode signal that generates an electric field that modulates the optical signal with a frequency dependent loss of not more than 0.8 dB per square root of an electrode signal frequency in GHz per centimeter in a frequency window of at least 10 GHz via the electro-optic effect, the frequency window in a frequency range to not more than five hundred GHz;
• and
• wherein a functionality of an optical device including the waveguide, the first engineered electrode, and the second engineered electrode is tailored by configuring compositions, shapes, dimensions, placements, and/or orientations of the first engineered electrode, the second engineered electrode, the first plurality of extensions, and the second plurality of extensions relative to a composition, cut, and/or cross-sectional profile of the ridge waveguide.