  Optical I/O plays a crucial role in the lifespan of lab-on-a-chip systems,
from preliminary testing to operation in the target environment. However, due
to the precise alignments required, efficient and reliable fiber-to-chip
connections remain challenging, yielding inconsistent test results and unstable
packaged performance. To overcome this issue, for use in single mode on-chip
systems, we propose the incorporation of area-enlarged grating couplers working
in conjunction with multimode fibers. This combination enables simpler, faster,
and more reliable connections than the traditional small area grating coupler
with single-mode fiber. In this work, we experimentally demonstrate a 3dB
in-plane (X, Y) spatial tolerance of (10.2 {\mu}m, 17.3 {\mu}m) for the large
area configuration, being at least (2.49, 3.33) times that of the small area
one, and agreeing well with theoretical calculations. The simple concept is
readily applicable to a range of photonic systems where cheaper more robust
optical I/O is desired.
