  We report a stable, low loss method for coupling light from
silicon-on-insulator (SOI) photonic chips into optical fibers. The technique is
realized using an on-chip tapered waveguide and a cleaved small core optical
fiber. The on-chip taper is monolithic and does not require a patterned
cladding, thus simplifying the chip fabrication process. The optical fiber
segment is composed of a centimeter-long small core fiber (UHNA7) which is
spliced to SMF-28 fiber with less than -0.1 dB loss. We observe an overall
coupling loss of -0.64 dB with this design. The chip edge and fiber tip can be
butt coupled without damaging the on-chip taper or fiber. Friction between the
surfaces maintains alignment leading to an observation of +-0.1 dB coupling
fluctuation during a ten-day continuous measurement without use of any
adhesive. This technique minimizes the potential for generating Raman noise in
the fiber, and has good stability compared to coupling strategies based on
longer UHNA fibers or fragile lensed fibers. We also applied the edge coupler
on a correlated photon pair source and observed a raw coincidence count rate of
1.21 million cps and raw heralding efficiency of 21.3%. We achieved an auto
correlation function g^(2) (0) as low as 0.0004 at the low pump power regime.
