Pluggable single-mode fiber-array-to-pic coupling using micro-lenses

Single-mode optical coupling between fiber and photonic integrated circuit (PIC) requires precision alignment and bonding, and significantly adds to the cost of photonic packaging. This article describes how a pair of micro-lens arrays-one on the Si-PIC and the other on the fiber-array- can be used to achieve fiber-to-PIC grating-coupling with an insertion-loss of 1.7 dB (i.e., a coupling efficiency of 68%) at 1300 nm, and a 1 dB alignment tolerance of ± 30 μm. Such relaxed tolerances allow for a “pluggable” connector to have a make-break insertion-loss reproducibility of 0.2 dB (one standard deviation).