LASER ASSISTED THERMAL POLING OF SILICA BASED WAVEGUIDES

摘要

A method of thermally poling a silica based waveguide (12) comprises exposin g a region of the waveguide (12) to an electric field (for example, via capillary electrodes (22, 24) inserted into holes in the waveguide); directi ng a laser beam (18) into the region exposed to the electric field to effect localised heating of the region via direct absorption; and scanning the lase r beam (18) over the region at a rate selected to avoid heating of the region above the glass transition temperature. Reversing the electric field while scanning the laser beam (18) allows the formation of periodic poled gratings . The waveguide (12) can comprise an optical fibre.