Photonetics SA and the Direction des Constructions Navales are making final tests on a wide range of optical sensors and systems to prove that optical networks are the way to go. Using silicon wafers, glass plates and fiber optics, the French Navy is testing optical detectors to keep track of such information as high pressure and dew points, and nuclear missile firing control networks. Designers say that in addition to cutting down on the wiring necessary aboard a wartime vessel, optical networks are more reliable than their electric counterparts and are not susceptible to electromagnetic radiation.