Optical coupling using a vernier scale

An optical edge coupling method comprising:

• positioning a first photonic device so that a first alignment waveguide from a plurality of alignment waveguides of the first photonic device is at least partially aligned with a first alignment coupler from a plurality of alignment couplers of a second photonic device, wherein the alignment waveguides are equally spaced a first length apart from each other along a first surface, and wherein the alignment couplers are equally spaced a second length apart from each other;
• detecting a first light from the alignment waveguides using at least one photodetector from a plurality of photodetectors of the second photonic device;
• and
• determining an alignment of the first photonic device and the second photonic device based on the detecting.

An apparatus comprising:

• a plurality of alignment couplers, wherein the alignment couplers are equally spaced a first length apart from each other along a first surface;
• a plurality of photodetectors optically coupled to the plurality of alignment couplers;
• a memory;
• and
• a processor coupled to the photodetectors and the memory, wherein the memory comprises computer executable instructions stored in a non-transitory computer readable medium that when executed by the processor cause the processor to:
• receive an electrical signal in response to at least one of the photodetectors detecting a first light;
• and
• determine an edge coupling alignment based on the electrical signal, wherein the edge coupling alignment is aligned when the electrical signal indicates two photodetectors of the plurality of photodetectors detect the first light, and wherein the edge coupling alignment is misaligned when the electrical signal indicates only one photodetector of the plurality of photodetectors detects the first light.