Abstract

For the production of single shot fiber Bragg gratings^1-3 in-line during the fiber drawing process, a knowledge of the effects of exposure conditions and material composition of fiber can be of crucial importance. During in-line production, one is not afforded the possibility of exposing the fiber incrementally to repeated laser shots until the correct grating reflectivity is achieved. Single shot writing of gratings in many different types of fibers indicates that the maximum index change in the Type I regime (<1 J/cm², yielding a spectrally narrow and smooth reflectivity) from a single shot is on the order 10^-5. For many applications (ie sensor arrays) this index change produces reflectivites that are more than adequate for good system performance. However, for certain applications greater reflectivies are required. In an effort to better control and possibly improve the photosensitivity of optical fibers at 248 nm we studied the growth dynamics of fiber Bragg gratings in various fibers under various exposure conditions.

© 1995 Optical Society of America