Photonic device with fiducial marks for alignment of an optical component

A method of assembly, the method comprising:

• obtaining a first photonic device comprising:
• an optically active layer;
• an epitaxial layer on the optically active layer;
• a waveguide that was patterned in a first patterning step and was defined by a waveguide etch;
• an etched facet extending through the epitaxial layer on the optically active layer, the etched facet was patterned in a second patterning step and was defined by a facet etch, and the etched facet having an optical coupling region optically coupled to the waveguide;
• and
• a fiducial mark configured for alignment of an optical component to the optical coupling region,
• wherein the fiducial mark has:
• a first portion was patterned in the first patterning step and was defined by at least a part of the waveguide etch;
• and
• a second portion comprising an edge extending through at least part of the epitaxial layer on the optically active layer, the edge of the second portion was patterned in the second patterning step and was defined by at least a part of the facet etch;
• aligning the first photonic device to a second photonic device using the first and second portions of the fiducial mark;
• and
• attaching the aligned first and second photonic devices together.

A method of fabrication of a photonic device on a substrate comprising an optically active layer and an epitaxial layer on the optically active layer, the method comprising:

• patterning in a first patterning step, and defining by at least a part of a waveguide etch, a first portion of a fiducial mark and a waveguide;
• patterning a mask in a second patterning step, a second portion of the fiducial mark and an etched facet;
• and
• forming, by at least a part of a facet etch masked by the patterned mask, the second portion of the fiducial mark and the etched facet, wherein the second portion of the fiducial mark is formed with an edge extending through at least part of the epitaxial layer on the optically active layer and wherein the etched facet is formed extending through the epitaxial layer on the optically active layer, the etched facet having an optical coupling region optically coupled to the waveguide,
• wherein the first and second portions of the fiducial mark are is configured for alignment of an optical component to the optical coupling region.