Nanotechnology researchers look to stabilize optical signals in high-speed networks

October 14, 2004 Singapore -- The Institute of Microelectronics (IME), a member of the Agency for Science, Technology and Research (A*STAR), has inked an agreement with Bussan Nanotech Research Institute (XNRI), wholly owned subsidiary of Mitsui & Co. Ltd. Japan, to collaborate on a research & development project aimed at stabilizing optical signals in high speed optical networks.

IME and XNRI will jointly develop a device to compensate for chromatic dispersion in optical signals, which causes data distortion over long distances in high-speed telecommunication networks. In optical fibers, waveforms or light signals broaden over long distances, making the signals difficult to interpret by the receiver. Chromatic dispersion in particular poses a major challenge as the effects increase non-linearly at the rate of the square of the increased speed of the transmission, e.g. chromatic dispersion at 10 Gbits/sec will be magnified by 16 times at 40 Gbits/sec. In addition, at 10 Gbits/sec, the distance over which the optical signal can be transmitted without any dispersion compensation is 30 km (assuming the optical network consists of standard dispersion singlemode fibers), but at 40 Gbits/sec, this distance is decreased to 2 km.

The problems of chromatic dispersion and transmission error are exacerbated as network speeds and span lengths increase. The market for such optical components is just emerging and the growth rate will quickly accelerate as the transmission rates increases. In addition, the mandatory and increased usage of chromatic dispersion compensators in network systems that deploy DWDM is expected to fuel the market growth of the device. According to industry analyst firm RHK, global demand for chromatic dispersion compensating devices should grow from $29 million this year to $47 million by 2007.

XNRI's solution is to create a compact photonic crystal-based chromatic dispersion compensator (CDC) on silicon-based wafers. According to the research institute, a photonic crystal-based device will reduce the power penalty of high-speed optical networks by at least 3 dB and offer significant cost savings over current dispersion compensators.

Based on XNRI's novel device design, IME will use its fabrication expertise in high- index contrast waveguides and silicon-based photonic crystals and optical packaging module design to develop a manufacturing process for XNRI's CDC device over the next two and a half years. IME will also conduct reliability testing of the devices to ensure ready-to-market completion. XNRI will provide the performance characterization of the CDC device by utilizing its proprietary technology for high accuracy chromatic dispersion measurement.

In working with IME, XNRI has first chosen a fabrication approach based on standard CMOS equipment and processes, as it will provide a "plug and play" solution while ensuring low cost and high yield in its production in foundries. "Our mission is to select technologies for further development, drawing on scientific and manufacturing know-how from around the world, bringing these technologies to the benchmark plant and then to mass production," explains Yoshihiko Shichida, director of XNRI. "We work with top research institutes, and we have no doubt that our collaboration with the IME will be mutually rewarding."

To date, XNRI has embarked on more than 30 joint research projects with research institutes and universities both in Japan as well as in Singapore, India, Brazil, Europe, and the United States.