Narrow linewidth excimer laser for inscribing Bragg gratings in optical fibers

Abstract

A spectrally narrow linewidth KrF excimer laser has been developed for the application of writing Bragg gratings in optical fibers. Two air spaced etalons 80 and 6 cm−1 have been incorporated within the laser cavity resulting in a laser line with a linewidth of approximately 4 pm. A stable wavelength setting for writing Bragg gratings has been achieved without the necessity of a feedback mechanism. A study of the formation of Bragg grating in optical fibers with this narrow linewidth KrF excimer laser has been carried out. High quality gratings have been demonstrated in hydrogen sensitized fibers with a pulse energy density as low as 20 mJ/cm2. Limitations and various problems encountered in inscribing Bragg gratings (such as two simultaneous grating lines) with the narrow linewidth excimer laser source are also discussed.