June 2016
Spotlight Summary by Francesco Morichetti
Ultralow crosstalk nanosecond-scale nested 2 × 2 Mach–Zehnder silicon photonic switch
Fast switching in silicon photonics gets record performance.
High-performance supercomputing and datacentre networks yearns for energy-efficient solutions for fast and high-capacity data switching in high-port-count nodes. Electronics is the current technology, but it is bound to resort soon to heavy parallelization and power-hungry multi-chip architectures; optical technologies already offer 3D-MEMS switches, which are however too slow for applications that require data-packet reconfiguration. Silicon photonics has the right stuff to become a key technology for low-power switch fabrics operating at nanosecond-scale. Yet, to date, high loss and high optical crosstalk limit the port-count of silicon photonic switches to a handful of I/Os.
In this Optics Letters article, N. Dupuis and coworkers present something that is likely to become a game-changing silicon photonic building block. The idea is rather simple indeed, essentially consisting of 2 × 2 nested-Mach-Zehnder switch where the conventional straight-line phase-shifter integrated in one arm is replaced by a Mach-Zehnder phase shifter. This design enables to fully exploit the energy-efficient and fast switching provided by free-carrier plasma dispersion effect in silicon waveguides, without paying the price of the inherent loss associated with free-carrier absorption. A record crosstalk value of -34.5 dB is achieved, with only 2 dB loss and a remarkably small switching time of 4 ns. Everything we need is monolithically integrated onto a small silicon chip, hosting the photonic switch, the CMOS driver and interface logic.
Another brick in the silicon photonic route towards energy efficient computing networks has been added.
You must log in to add comments.
Add Comment
You must log in to add comments.
Article Information
Ultralow crosstalk nanosecond-scale nested 2 × 2 Mach–Zehnder silicon photonic switch
Nicolas Dupuis, Alexander V. Rylyakov, Clint L. Schow, Daniel M. Kuchta, Christian W. Baks, Jason S. Orcutt, Douglas M. Gill, William M. J. Green, and Benjamin G. Lee
Opt. Lett. 41(13) 3002-3005 (2016) View: Abstract | HTML | PDF