A multi-channel fiber-optic bench with stamped mirrors for avionic transceivers

Avionic transceivers require feedthroughs that couple light between optical fibers and photonic elements such as vertical cavity surface emitting lasers (VCSELs) and photodiodes (PDs). A right-angle turn is generally necessary since light exits or enters VCSELs and PDs normal to the substrate surface, and it is preferable for the fibers to be routed parallel to the substrate surface. This turn can be implemented in the optical path using separate lenses or incorporated into the feedthrough element, or by using a flex-circuit bent 90 degrees. This paper describes a new approach that uses stamped, metallic, micro-mirrors that are monolithically integrated into a metallic, low-profile, fiber-optic feedthrough. The curved surface in the micro mirrors can both fold the optical beam and focus the light, providing two functions in a single optical element. This concept is successfully demonstrated by measuring the coupling efficiency in an optical connection between two single-mode optical fibers, which is even more challenging than multi-mode fiber-optic connections that are common in avionics.