Photonic devices and methods of forming the same

A method comprising:

• forming a waveguide that comprises a base layer and a protrusion over the base layer;
• depositing an insulating layer on the waveguide;
• performing a deposition process and a patterning process to form a first metal film and a second metal film, wherein the first metal film and the second metal film are higher than the base layer and lower than a top end of the protrusion, and wherein the first metal film is on an opposing side of the protrusion than the second metal film, and is spaced apart from the second metal film by a first spacing;
• depositing an additional insulating layer over the first metal film and the second metal film;
• and
• forming a ground electrode and a signal electrode in the additional insulating layer and connecting to the first metal film and the second metal film, respectively, wherein the ground electrode is spaced apart from the signal electrode by a second spacing greater than the first spacing, and wherein the first metal film, the second metal film, the ground electrode, the signal electrode, and the waveguide collectively form an electro-optic modulator.

A structure comprising:

• an insulating layer;
• a waveguide over the insulating layer, wherein the waveguide comprises a baser layer and a protrusion over and joined to the base layer;
• a first electrode and a second electrode on opposing sides of the protrusion;
• a first metal film electrically connected to the first electrode;
• and
• a second metal film electrically connected to the second electrode.