IPG calls IMRA infringement case "incompetent"

13 Jan 2011

War of words heats up in the battle for fiber laser supremacy, as a settlement conference is scheduled for January 27.

In its latest filing to the court presiding over the ongoing litigation between IPG Photonics and IMRA America, IPG has labelled its rival fiber laser maker’s evidence of patent infringement as “incompetent”.

Filed with the Eastern District of Michigan District Court on January 10, IPG’s strongly worded motion also states IPG’s position that “no reasonable jury could find that IPG willfully infringes any claim of US Patent No. 5,818,630”.

While IPG suffered a recent setback when the presiding judge Arthur Tarnow decided to adopt IMRA’s definitions relating to some key technological details of fiber laser designs, the Oxford, Massachusetts company has come out fighting with its motion for summary judgment of no infringement of that patent.

IMRA first brought the case against its rival, which dominates the fiber laser sector, in 2006. But only now does the case finally appear to be heading towards a conclusion.

The patent in question was awarded to Martin Fermann and Don Harter from IMRA in 1998, and its definitions and claims are at the heart of the court battle. In its latest motion, IPG said, “IMRA has not shown any evidence, or any basis for any allegation, that IPG’s products contain an equivalent to the claimed “mode converter” required by all claims of the ‘630 patent.”

Going further, IPG’s attorney Kurt Glitzenstein argues that the first claim of the ‘630 patent is invalid for “indefiniteness”. At an earlier stage of the case, IPG had requested that the ‘630 patent was re-examined. In 2009, the US Patent Office confirmed its validity, whereupon IPG requested a second examination. The court rejected that request, although IPG’s subsequent request for a reconsideration is still pending.

”Hand-waving” opinion
In its latest motion, IPG also laid into IMRA’s expert witness Wayne Knox, the director of the Institute of Optics at the University of Rochester, saying: “Dr. Knox’s opinions are at best hand-waving and thus not competent evidence on which IMRA can meet its burden on infringement.”

Knox has appeared on behalf of IMRA in the case, and IPG believes that the infringement allegations that have been put forward to the court rest entirely on his opinion, set forth in two reports.

Knox’s reports state that the all-important mode conversion process takes place as light passes through a splice between two optical fibers. Each fiber has a different refractive index, and the splice ensures that there is a smooth transition between the two index profiles – from a passive single-mode fiber to a multi-mode active fiber that delivers the optical gain required for high-energy lasing.

However, IPG’s defense against the IMRA accusations includes the assertion that Knox has not actually looked inside any IPG products to observe such splicing, and that the expert’s testimony was based solely on the results of three RSoft simulations.

Judge Tarnow recently decided that IMRA’s preferred term of “mode converter” would be used in the ongoing proceedings, such that it is “an element capable of matching the mode of a multi-mode amplifier fiber”. IPG had previously suggested an alternative description, but the latest motion now argues that this means the mode converter should be clearly conceived as a discrete component – something that, it goes on to say, does not exist in any IPG products:

“No reasonable jury could conclude that ‘physically melting the materials [of the two fibers] and melting them together’ is a ‘discrete component’ or ‘element.’ There is nothing discrete or elemental about two materials melted together. Nor is the melted material a ‘component’,” states IPG in its defense.

The company also states that it achieves mode conversion by careful manufacture of its own fibers, such that the mode-field diameter of the single-mode fiber is effectively “pre-matched” to that of the fundamental mode of the multi-mode gain fiber.

Glitzenstein concludes the IPG motion by requesting a summary judgment of “no infringement, invalidity, and no willful infringement” of the ‘630 patent.

The court has now scheduled a status/settlement conference on January 27 at the Theodore Levin Courthouse in Detroit, at which both parties have been told to appear in person before Judge Tarnow at 2pm. The case continues.