Optical integrated circuit systems, devices, and methods of fabrication

An optical integrated circuit device comprising:

• a semiconductor substrate;
• a metal structure comprising an opening and disposed over the semiconductor substrate;
• a waveguide made of a first material disposed in the opening of the metal structure;
• a cladding structure disposed in the opening and between the waveguide and the metal structure;
• an extension made of the first material, the extension being disposed below the metal structure, wherein the extension comprises a first portion outside the opening and a second portion extending through the opening and physically contacting the waveguide;
• and
• an electrostatic discharge (ESD) protection structure electrically coupled to the extension.

An optical integrated circuit device comprising:

• a semiconductor substrate;
• a first waveguide made of a first material and disposed over the semiconductor substrate, the first waveguide comprising a first parallel region and a first tapered region, wherein the first waveguide is configured to transmit a first optical signal in a first direction through the first waveguide;
• a second waveguide made of the first material disposed over the semiconductor substrate, the second waveguide comprising a second parallel region and a second tapered region, wherein the second waveguide is configured to transmit a second optical signal in a second direction parallel to the first direction through the second waveguide, and wherein the second waveguide is adjacent to and separated from the first waveguide;
• a first extension made of the first material and disposed over the semiconductor substrate, the first extension physically contacting the first waveguide, wherein the first extension extends away from the first waveguide in a third direction comprising a first component perpendicular to the first direction;
• and
• an electrostatic discharge (ESD) protection structure electrically coupled to the first extension.