Photosensitivity in optical fiber waveguides: From discovery to commercialization

The photosensitivity of germanium-doped-core optical fibers was discovered more than twenty years ago. The discovery provided a means for photoimprint ing gratings in the core of optical fibers, and eventually photosensitivity became an important technology for fiber-optic communications. This paper recounts briefly the story of the photosensitivity of optical fiber wavegui des and the significant developments that occurred on the journey from its discovery to its commercialization. As is often the case with many inventio ns, the discovery was serendipitous. Furthermore, several technical and non technical developments were necessary before the discovery could be exploit ed commercially. In the case of photosensitivity, the time span from discov ery to commercialization was relatively long-about 15 years.