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
$\pm ~30~\mu \text{m}$
. Such relaxed tolerances allow for a “pluggable” connector to have a make-break insertion-loss reproducibility of 0.2 dB (one standard deviation).