Strictly Non-Blocking 8 × 8 Silicon Photonics Switch Operating in the O-Band

In this article, we report the development of a strictly non-blocking 8 × 8 silicon photonics switch designed to operate in the O-band. This 8 × 8 switch is based on path-independent insertion-loss topology and is composed of 2 × 2 thermo-optic double Mach-Zehnder switches and adiabatic intersections. The fabricated 8 × 8 switch chip is electrically packaged with a ceramic chip carrier and inserted into a socket on a printed circuit board. As for the optical connection, an optical fiber array and edge couplers are used. The fabricated 8 × 8 switch exhibits an average fiber-to-fiber insertion loss of 16.6 dB, including a fiber to chip coupling loss of 11.2 dB and crosstalk of less than -30 dB over a bandwidth of 70 nm. Moreover, we investigate the nonlinear characteristics of Si devices in the O-band. The cw input/output response and degradation free 28-Gb/s OOK signal transmission demonstrate that two-photon absorption and four-wave mixing are not significant when the input power is less than approximately 4 mW. These results indicate that it is possible to produce low-loss and low-crosstalk silicon photonics switches that operate in the O-band.