Fujitsu Files Lawsuit Against Tellabs

A lawsuit has been filed against Tellabs Inc by Fujitsu Ltd for allegedly infringing on four optics-related patents.

The suit, filed in the U.S District Court for the Eastern District of Texas, seeks unspecified pecuniary damages along with an injunction order against Tellabs.

There are four patents listed as a part of the lawsuit - Nos. 5,526,163; 5,521,737; 5,386,418; and 6,487,686 - all relate to optical communications technologies, along with intellectual property associated with Sonet, SDH, and DWDM.

The lawsuit is based on claims by Fujitsu that Tellabs 7100 Optical Transport System, which includes the 5500 and 6300 series, infringes upon patents made by Fujitsu - however the corresponding Fujitsu products aren’t yet known.

A Fujitsu spokesperson has stated that “there isn’t one specific product, it’s more of the technology and the intellectual property in general”.

Of the four patents listed, two relate to optical amplification, one relates to timing and synchronization, and the last describes error correction in transport. Three of these patents were registered by Fujitsu in the mid 1990s, making them relatively old by technology standards.

According to Heavy Reading senior analyst Sterling Perrin, it is unlikely that the suit relates to the switch fabric in Fujitsu’s new Flashwave 9500 range. The dispute is more likely to be in reference to Fujitsu’s older 7500 Flashwave ROADM range, Perrin stated, adding that “optical amplifiers are related to the 7500, and I believe error correction would be as well”.

According to a spokesperson, Tellabs “believes the case is without merit”, though they are still in the process of reviewing the case.