Single lens photometric machine vision with 3D imaging for fiber-to-chip coupling

A single lens photometric machine vision (SLPMV) optical microbench is presented and built for fiber-to-chip coupling. By a rotation mechanics in SLPMV, the multi-view-camera can scan the various surface status of the chips coupled. To realize 3D imaging more explicitly, the modified photometric stereo algorithm is proposed through acquiring the images of weak saturation, matching the scanning illuminative angles, and rectifying rectangularly the original images. The reconstructed images have had similar qualities as those obtained by scanning electron microscopy and have unveiled the detailed information obscured in the 2D images. For the InP-based optical waveguide chip coupled with wedge-shaped fiber, the insertion loss tested on the SLPMV is 3 dB less than one on the conventional testing station. The SLPMV could serve as a more cost-effective and compact scientific observation instrumentation in imaging informatics than commercial ones.