Kawasaki, Japan--Fujitsu Laboratories Limited announced that it has been able to halve the power consumption of an optical waveguide switch based on silicon photonics through the world's first use of fine-patterned silicon germanium (SiGe) for this application, rather than conventional silicon (Si). This integrated photonics achievement will allow for high-speed optical switches capable of operating across a wide range of wavelengths, while featuring the world's lowest power requirements.
In accordance with the constant rise of data volume being transmitted over networks, likewise, the power consumption of networking equipment shows a continuous growth trend, leading to concerns for a potentially serious energy problem in the future. Fujitsu's newly-developed technology will help contain power consumption while supporting large-volume network traffic, thus enabling high-end services linking multiple cloud networks and ultra-high-definition videoconferencing, among other applications.
Details of this technology will be presented at the 23rd Annual Meeting of the IEEE Photonics Society (PHO 2010), being held from November 7-11 in Denver, CO.
Parts of this research were undertaken as part of the work of the Vertically Integrated Center for Technologies of Optical Routing toward Ideal Energy Savings (VICTORIES) project, as part of the program The Formation of Innovation Center for Fusion of Advanced Technologies, sponsored by the Special Coordination Funds for Promoting Science and Technology, of Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT).
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 has developed the world's first optical switching element that uses fine-patterned SiGe in the refractive-index modulator. Forming fine-patterned SiGe, which has a narrower bandgap than Si, on top of Si allows for more efficient electron accumulation, and therefore less power is required for switching.
Prototype optical switch devices developed by Fujitsu operated 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.
SOURCE: Fujitsu; www.fujitsu.com/global/news/pr/archives/month/2010/20101109-02.html
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