Fujitsu Research Laboratories is experimenting with a pair stable semiconductor laser processing unit designed to process optical signals without converting them to electrical ones: the optical signal processing unit consists of three paired stable semiconductor lasers, each able to amplify the signal from the cable, extract data and generate a new signal; the device is 0.4mm square – much more highly integrated than British Telecom’s 2cm optical switch, says Fujitsu smugly – and the Japanese firm hopes to use it as a super-high speed data processing device for transmission of large amounts of optical data over Integrated Services Digital Networks.