Fiber array unit and photonics device

A photonics device, comprising:

• a fiber array unit comprising a transparent structure, the transparent structure having an observing surface and a mating surface substantially parallel to each other, the observing surface and the mating surface being on a same light path, the transparent structure having a first alignment pattern formed on the mating surface, at least a portion of the first alignment pattern being transparent, wherein the first alignment pattern is axially symmetrical about two axes, and the two axes are perpendicular to each other wherein the fiber array unit further comprises a plurality of optical fibers entering the transparent structure via an entrance surface, at least a portion of the optical fibers is exposed from the mating surface, and the mating surface is different from the entrance surface;
• and
• a substrate comprising a second alignment pattern disposed thereon, wherein the second alignment pattern is axially symmetrical about two axes that are perpendicular to each other, and a spatial frequency of the first alignment pattern is equal to or similar to a spatial frequency of the second alignment pattern,
• wherein the first alignment pattern and the second alignment pattern are overlapped and aligned.