Poling Optical Fibers with Electrical Corona Discharge

Silicate optical fiber does not exhibit a linear electrooptic effect (Pockels’) because the material is symmetric. Poling can be used to induce the Pockels effect in pieces of fiber with electrodes by creating a permanent electric field by applying high voltage while the fiber is excited thermally [1] or optically [2] . The second-order nonlinear coefficient achieved reproducibly is χ (2) ≈ 0.1-0.3 pm/V. Optical poling uses short-wavelength light to excite the fiber core (e.g., from a UV lamp [3] ) as high voltage is applied to the internal fiber electrodes. Although the recorded field is limited by the voltage applied and silica’s dielectric breakdown strength, low loss devices can be fabricated. Here we describe the use of electrical corona discharge to pole fibers with high electric field across the fiber core. Charges deposited on the fiber surface (due to the electrical corona discharge) create the necessary poling field, as previously demonstrated in planar waveguides [4] .