Ultra-compact 32 × 32 strictly-non-blocking Si-wire optical switch with fan-out LGA interposer

We demonstrate a 32 x 32 path-independent-insertion-loss optical path switch that integrates 1024 thermooptic Mach-Zehnder switches and 961 intersections on a small, 11 x 25 mm(2) die. The switch is fabricated on a 300-mm-diameter silicon-on-insulator wafer by a complementary metal-oxide semiconductor-compatible process with advanced ArF immersion lithography. For reliable electrical packaging, the switch chip is flip-chip bonded to a ceramic interposer that arranges the electrodes in a 0.5-mm pitch land grid array. The on-chip loss is measured to be 15.8 +/- 1.0 dB, and successful switching is demonstrated for digital-coherent 43-Gb/s QPSK signals. The total crosstalk of the switch is estimated to be less than -20 dB at the center wavelength of 1545 nm. The bandwidth narrowing caused by dimensional errors that arise during fabrication is discussed. (C) 2015 Optical Society of America