So to consider what POET has achieved in terms of the accuracy to fix optical chips into an exact position along the X, Y and Z axis for coupling to the waveguides. They are reporting submicron alignment.

What does submicron look like? And keep in mind the ability for efficient coupling also requires the material set and structures that shape and steer the light beams. POET’s secret sauce which is a highly guarded secret even within the company.

https://www.bench.com/setting-the-benchmark/how-big-is-a-micron