We fabricate a 32 × 32 silicon photonics switch on a 300-mm silicon-on-insulator wafer by using our complementary metal-oxide-semiconductor pilot line equipped with an immersion ArF scanner and demonstrate an average fiber-to-fiber insertion loss of 10.8 dB with a standard deviation of 0.54 dB, and on-chip electric power consumption of 1.9 W. The insertion loss and the power consumption are approximately 1/60, and less than 1/4 of our previous results, respectively. These significant improvements are achieved by design and fabrication optimization of waveguides and intersections on the chip, and by employing a novel optical fiber connector based on extremely-high-Δ silica planarlightwave-circuit (PLC) technology. The minimum crosstalk was −26.6 dB at a wavelength of 1547 nm, and −20-dB crosstalk bandwidth was 3.5 nm. Furthermore, we demonstrate low-crosstalk bandwidth expansion by using output port exchanged element switches. We achieve a −20 dB crosstalk bandwidth of 14.2 nm, which is four-times wider than that of the conventional element switch based 32 × 32 switch.

We, for the first time, present the ultrafast optical nonlinear response of a hydrogenated amorphous silicon (a-Si:H) wire waveguide using femtosecond pulses. We show cross-phase and cross-absorption modulations measured using the heterodyne pump-probe method and estimate the optical Kerr coefficient and two-photon absorption coefficient for the amorphous silicon waveguide. The pumping energy of 0.8 eV is slightly lower than that required to achieve two-photon excitation at the band gap of a-Si:H (approximately 1.7 eV). An ultrafast response of less than 100 fs is observed, which indicates that the free-carrier effect is suppressed by the localized states in the band gap.

We demonstrate a 32 × 32 path-independent-insertion-loss optical path switch that integrates 1024 thermooptic Mach-Zehnder switches and 961 intersections on a small, 11 × 25 mm2 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.

We demonstrate a low-crosstalk 2 x 2 thermo-optic switch with silicon wire waveguides. The device is based on a 2 x 2 array of Mach-Zehnder interferometer (MZI) switches. Lowest crosstalk levels of -50 dB and -30 dB are obtained for 'bar' and 'cross' switching states, respectively. An intersection in the switch is important for low-crosstalk operation. The power consumption of one MZI element switch is 40 mW and the total power consumption of the device is at most 160 mW.

We report on a path-independent insertion-loss (PILOSS) 8 × 8 matrix switch based on Si-wire waveguides, which has a record-small footprint of 3.5 × 2.4 mm2. The PILOSS switch consists of 64 thermooptic Mach-Zehnder (MZ) switches and 49 low-crosstalk intersections. Each of the MZ switches and intersections employs directional couplers, which enable the composition of a low loss PILOSS switch. We demonstrate successful switching of digital-coherent 43-Gbps QPSK signal.