A common spec for the VIPA

Fujitsu Limited and Avanex Corporation have reached an agreement to standardise specifications on virtually imaged phased array dispersion compensation modules.

Fujitsu Limited and Avanex Corporation have reached an agreement to standardise specifications on virtually imaged phased array (VIPA) dispersion compensation modules.

In optical transmission systems, optical signals become distorted (wavelength dispersion) during transmission through optical fibres. Dispersion compensation modules correct such distortion and return signals to their original state. Hence, the modules are considered indispensable to realising next-generation 40 Bbit/sec optical transmission systems.

Until now, conventional optical transmission systems that operate at 10 Gbit/sec have corrected wavelength dispersion by using a dispersion compensating fibre (DCF). Next-generation high-speed optical transmission systems, however, require higher performance wavelength compensation devices, such as ‘tunable’ types, capable of making minute corrections to wavelength dispersion, which changes according to environmental factors such as the type and length of fibre as well as temperature.

Since 1998, Fujitsu and Avanex have been separately developing new tunable-type dispersion compensation modules that use VIPA technology. Based on this new agreement, they will standardise specifications for such things as mechanical characteristics (fixing method), module size, optical characteristics (insertion loss), tunable dispersion range, driving voltage and control method. In addition, they will standardize guidelines for dispersion compensation management. Fujitsu and Avanex also plan to sign a multi-source agreement.

According to market research company RHK, the worldwide market for dispersion compensation modules is expected to grow from $177 million (about 20 billion yen) in 2000 to $433 million (about 50 billion yen) in 2004. In 2000, DCF constituted a great part of this market; however, with the spread of high-speed optical transmission systems, which require higher-performance dispersion compensation, the share of tunable dispersion compensation equipment is anticipated to increase.

Fujitsu is currently sampling VIPA-type dispersion compensation modules for 10 GBit/sec optical transmission systems and plans to start volume shipments in late 2001. Moreover, it is now developing VIPA-type dispersion compensation modules for next- generation 40 GBit/sec systems, with product shipments expected to begin in 2002.

Avanex is currently marketing the VIPA dispersion compensator devices under the trademark of PowerShaper. The PowerShaper product for 10 GBit/sec OC-192 transmission is in pilot production. The PowerShaper products for 40 GBit/sec have already successfully passed a number of field trials. Pilot production is planned for the second half of 2001.

On the web