Efficient silicon-on-insulator fiber coupler fabricated using 248-nm-deep UV lithography

We present a silicon-on-insulator (SOI) waveguide to fiber coupler fabricated using 248-nm-deep ultraviolet lithography. The loss of the taper structure is around 1 dB while the coupling loss from a lensed fiber into a 590-nm-wide SOI waveguide was measured to be 1.9 dB.