Date: 09/11/2010

SiGe based optical switch from Fujitsu cuts power consumption by half

Fujitsu Laboratories Limited has developed an optical switch using silicon germanium (SiGe) material instead of pure silicon semiconductor material. SiGe based semiconductor devices reduce power consumption and operate at higher speeds compared to Silicon. Fujitsu has used fine-patterned SiGe to enable switches operate in a wide range of wavelengths. SiGe offers narrow band-gap than Si and allows more efficient electron accumulation resulting in low power consumption.

Large-scale optical-waveguide switches operate multiple optical switching elements simultaneously. The heat that this generates can degrade device performance, which necessitates the lowest possible power consumption for each optical switching element.

With optical switching elements, the application of an electrical current to the refractive-index modulator causes electrons to accumulate in fine waveguides, which modulates the refractive index and switches the output port . With conventional optical switching elements made using fine-patterned Si, the electron-accumulation efficiency in fine Si waveguides is low, necessitating more current to achieve sufficient electron-accumulation, thereby increasing power consumption.

Fujitsu says its prototype optical switch devices operate on 1.5 mW of power, approximately half the power required for conventional fine-patterned Si optical switching elements. This represents the lowest power requirement in the world for an optical switching element capable of high-speed operation across a wide range of wavelengths, claims Fujitsu.

Fujitsu is presenting the details of this technology at 23rd annual meeting of the IEEE Photonics Society (PHO 2010), being held from November 7-11 in Denver, Colorado, U.S.