Ultrafast and short-pulsed fiber laser developer IMRA America Inc. of Ann Arbor, Mich., said it has filed a lawsuit against IPG Photonics Corp., an Oxford, Mass., maker of fiber lasers and amplifiers, alleging it misused IMRA's intellectual property “following their refusal to enter into a serious license negotiation,” IMRA said in a statement. IPG Photonics recently terminated license negotiations after months of discussion. IMRA said its technology is used to obtain high-power and high-pulse energy from fiber lasers. It has licensed this technology to fiber laser and component manufacturers including Nufern, SPI Lasers and Aculight Corp and has more than 40 related US patents. IMRA announced on Dec. 5 that it signed a license agreement with Aculight Corp., a Bothell, Wash., maker of laser systems for defense, aerospace and medical applications, for IMRA’s amplification technology, US Patent No. 5,818,630, “Single-Mode Amplifiers and Compressors Based on Multi-Mode Fibers” and related patents, involving products that use large mode area (LMA), double-clad (DC) fibers.