DIRECT DETERMINATION OF THE QUADRATIC ELECTROOPTIC COEFFICIENT IN AN A-SI-H BASED WAVE-GUIDE

The first direct determination of the quadratic electro-optic coeffici ent, s, of a-Si:H at lambda = 1.3 mu m from measurements of the electr o-optic effect in an a-Si:H based waveguide is reported. From 'ac' exp eriments in which voltage pulses at a frequency of about 500 Hz were u sed, a direct determination of s yields the value of 2 X 10(-14) (cm/V )(2). Using this result to interpret the electro-optic effect in 'dc' experiments, estimates are obtained for the interface charge density a t the boundary between a:Si-H and a-SiNx:H cladding layers.