  Large port count spatial optical switches will facilitate flexible and energy
efficient data movement in future data communications systems, especially if
they are capable of nanosecond-order reconfiguration times. In this work, we
demonstrate an 8x8 microring-based silicon photonic switch with software
controlled switching. The proposed switch architecture is modular as it
assembles multiple identical components with multiplexing/demultiplexing
functionalities. The switch is fully non-blocking, has path independent
insertion loss, low crosstalk and is straightforward to control. A scalability
analysis shows that this architecture can scale to very large port counts. This
work represents the first demonstration of real-time firmware controlled
switching with silicon photonics devices integrated at the chip scale.
