Techniques for fabricating waveguide facets and die separation

A method, comprising:

• arranging a plurality of dice on a substrate;
• performing a first etching process that etches a first layer of the substrate at a boundary between adjacent dice of the plurality of dice on the substrate, wherein the first etching process forms facets of one or more waveguides that are defined within the first layer;
• performing a second etching process that etches a second layer beneath the first layer, the second etching process forming a trench in the boundary, wherein the second layer has a different material from the first layer;
• and
• separating the adjacent dice of the plurality of dice along a region that is displaced from the trench.

A method, comprising:

• arranging a plurality of dice on a substrate;
• performing a first etching process that etches a first layer of the substrate at a boundary between adjacent dice of the plurality of dice on the substrate, wherein the first etching process forms facets of one or more waveguides that are defined within the first layer, and wherein the first etching process leaves behind bridge portions of the first layer in the boundary;
• patterning polymer material over the bridge portions of the first layer in the boundary;
• and
• performing a second etching process that etches through a third thickness of a bulk portion of the substrate beneath a second layer, and through a second thickness of the second layer such that the plurality of dice are connected to a remainder of the substrate or to each other via the bridge portions and the patterned polymer material.