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.
Significant advances in microwave and millimeter wave technology over the past decade have enabled the development of a new generation of imaging diagnostics for current and envisioned magnetic fusion devices. Prominent among these are revolutionary microwave electron cyclotron emission imaging (ECEI), microwave phase imaging interferometers, imaging microwave scattering and microwave imaging reflectometer (MIR) systems for imaging T e and n e fluctuations (both turbulent and coherent) and profiles (including transport barriers) on toroidal devices such as tokamaks, spherical tori and stellarators. The diagnostic technology is reviewed, and typical diagnostic systems are analyzed. Representative experimental results obtained with these novel diagnostic systems are also presented.
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We fabricated and characterized a silicon photonics 8 × 8 strictly non-blocking optical switch based on double-Mach-Zehnder (MZ) element switches. The double-MZ switches, each of which consisted of an intersection and two asymmetric MZ switches, enabled the suppression of crosstalk across a wide wavelength range. The 8 × 8 switch exhibited an average fiber-to-fiber insertion loss of 11.2 dB and -20 dB crosstalk in a bandwidth wider than 30 nm. Furthermore, we constructed an 8 × 8 polarization-diversity switch by using two 8 × 8 switches and demonstrated 32-Gbaud dual-polarization, quadrature-phase-shift-keying, four-channel wavelength-division-multiplexed signal transmission without significant signal degradation.
We fabricate and characterize a polarizationdiversity 32 × 32 silicon photonics switch by newly introducing SiN overpass waveguides onto our nonduplicate polarization-diversity path-independent insertion-loss switch. The SiN overpass waveguides are used to simplify the optical paths with a uniform path length between the edge couplers and the switch matrix and significantly reduce the number of waveguide intersections. The switch chip is fabricated using a 300-mm silicon-on-insulator wafer pilot line. The fabricated switch comprises more than 7,600 components, making this the largest ever complementary-metal-oxidesemiconductor-based silicon photonics circuit. The switch chip is electrically and optically packaged and evaluated for a sampled port connection with 32 paths, with an average on-chip loss of ∼35 dB and an average polarization-dependent loss of 3.2 dB where 75% of the measured paths exhibit a loss of less than 3 dB. The differential group delay is measured to be 1.7 ps. The performance can be further improved by optimizing the device design.
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