Nullary Sources

Sebastian Anthony, writing for ExtremeTech:

There are two key breakthroughs here. First, IBM has managed to build a monolithic silicon chip that integrates both electrical (transistors, capacitors, resistors) and optical (modulators, photodetectors, waveguides) components. Monolithic means that the entire chip is fabricated from a single crystal of silicon, on a single production line; i.e. the optical components are produced at the same time as the electrical components, using the same process. There aren’t two separate regions on the chip that each deal with different signals; the optical and electrical components are all mixed up together to form an integrated nanophotonic circuit.

Second, and perhaps more importantly, IBM has manufactured these chips on its 90nm SOI process — the same process that was used to produce the original Xbox 360, PS3, and Wii CPUs. According to Solomon Assefa, a nanophotonics scientist at IBM Research who worked on this breakthrough, this was a very difficult step. It’s one thing to produce a nanophotonic device in a standalone laboratory environment — but another thing entirely to finagle an existing, commercial 90nm process into creating something it was never designed to do. It sounds like IBM spent most of the last two years trying to get it to work.

This could potentially be a really big deal. The power and heat profiles of optical systems are different from those of electrical systems.