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Characterization of the effects of different lasers on the tensile strength of fibers during laser writing of fiber Bragg gratings

Fibre Bragg gratings (FBGs) continue to be used in a wide variety of different telecommunications products such as filters, pump stabilisers and dispersion compensators. The increased specifications being demanded by successive generations of FBG components mean that higher manufacturing controls are needed to ensure high quality performance. One of the key areas of concern has been the effect of the laser exposure on the tensile strength of the fibre, since this affects yield, quality and lifetime of the FBG device. No comparative study has, to the best of our knowledge, so far been conducted to measure the relative merits of different exposure conditions. We present measurements of the degradation of the strengths of Corning SMF28 and intrinsically photosensitive fibres from laser exposure with the following lasers: excimer lasers at 193nm and 248nm and argon-ion laser at 244nm. A comparison is presented of the fibre pull strengths under varying illumination conditions with the different laser systems and a methodology established for favourable exposure conditions for FBG writing with reduced fibre strength degradation.