An optical switch will route an incoming optical signal from an input to a destination output without converting the light to electrical signal. It has the potential to enable ultra-high capacity optical networks that can deliver large volumes almost at the speed of light. An optical switch can be significantly miniaturized using silicon photonics, which is based on the same technology used to make computers chips. Fast, nanoscale silicon photonic optical switches can also enable emerging applications in computing architectures such as optically interconnected processors and memories.
So far the bulk of the research efforts on silicon photonic switches have been focused on integrating as many devices on a single chip. Instead of putting the whole switch on a single chip, our work proposes, to divide it over multiple chips. Like computers have moved from a single processor to multi-core architectures our switch uses multiple chips to guide the light to the desired output. We demonstrated a proof-of-concept for 8 inputs - 8 outputs switch fabric by assembling multiple photonic chips offering multiplexing functionalities. The proposed switch can guide the light from any input to any output, can scale to a large number of inputs and outputs, it is straightforward to control, and is compatible with the standard silicon chips manufacturing process.
This modular or “divide and conquer” approach for photonic integrated circuits offers the advantage of piece-wise manufacturing, packaging, assembly, and fewer electrical controls. It paves the way to create large scale systems from standard chips, which can be stacked like LEGO blocks to create 2.5 dimensional photonic systems.
More information : D. Nikolova, et. al., "Modular architecture for fully non-blocking silicon photonic switch fabric", Nature Microsystems & Nanoengineering 3, 16071 (2017), doi:10.1038/micronano.2016.71
High radix, low latency, energy efficient optical switches are essential to sustain the rapid growth in aggregate bandwidth requirements in data centers and high performance computers. Higher port count switches not only permit to interconnect more hosts directly but they also allow more compact topologies involving less links and switches to interconnect large networks. Starting with detailed device models which I have developed and experimentally verified, I analyzed the scalability of silicon photonic microring based switch fabrics with the widely used Benes topology. I was able to estimate the crosstalk and losses of a single chip switch fabric. This allowed me to determine the achievable port count and bandwidth density for these switch fabrics. The surprising conclusion of this was work was that the on-chip waveguide crossings contribute significantly to the scaling of a two dimensional switch fabric
2D switch fabric from double microring switching elements with Benes topology ; top left inset shows picture from a fabricated device; top right - schematics of the operation of the switching element; right inset - picture of a on-chip waveguide crossing; bottom - miltiple crossings model.
I am a scientist and an engineer with wide interests in photonics, optical enineering, deep learning and biology.