Ultralow loss single layer submicron silicon waveguide crossing for SOI optical interconnect.

We demonstrate compact, broadband, ultralow loss silicon waveguide crossings operating at 1550 nm and 1310 nm. Cross-wafer measurement of 30 dies shows transmission insertion loss of - 0.028 ± 0.009 dB for the 1550 nm device and - 0.017 ± 0.005 dB for the 1310 nm device. Both crossings show crosstalk lower than - 37 dB. The devices were fabricated in a CMOS-compatible process using 248 nm optical lithography with a single etch step.