Silicon modulators could enable laptop supercomputers

Scientists at IBM Research (Yorktown Heights, NY) have developed silicon Mach-Zehnder electro-optic modulators so tiny that supercomputers-consisting of thousands of individual processor “brains” connected by miles of copper wires-could one day fit into a laptop personal computer using the same amount of energy expended by a light bulb. Laser light input to a silicon chip travels down a silicon nanophotonic waveguide to the input of the optical modulator, a very fast “shutter” that controls whether the input laser is blocked or transmitted to an output waveguide-essentially using light on the chip to replace electrical signals. While other silicon optical modulators can operate at 40 Gbit/s, the length of these devices is on the order of 5 mm. The IBM modulator is only 200 µm long which, together with some other factors, makes this device about 1000 times smaller on a chip than comparable technologies. The report on this work, “Ultra-compact, low RF power, 10 Gbit/s silicon Mach-Zehnder modulator,” is published in Volume 15 of Optics Express. Contact J. Michael Loughran at [email protected].