Planar-integrated free-space optical fan-out module for MT-connected fiber ribbons

This paper reports on the design, the fabrication, and the testing of a compact planar-integrated free-space optical 1 /spl rarr/ 4 fan-out module for fiber ribbons with multifiber-terminated connectors. It supports 12 parallel optical channels and consists of a cascade of basic cells with 1 /spl rarr/ 2 fan-out. The module was implemented with surface-relief diffractive-phase elements; design and fabrication of the optical system were optimized for low loss by various measures such as the use of dielectric and silver reflective coatings. In experimental tests, a coupling efficiency of -11.4 dB per fan-out channel was obtained.