Second-harmonic generation in periodically poled silicon waveguides with lateral p-i-n junctions

Electric-field-induced second-harmonic generation is demonstrated in silicon waveguides with reverse biased lateral p-i-n junctions. Phase matching is achieved by periodically poling the applied electric field. Two different poling configurations are compared: in the first, the p- and n-type doped regions of the junctions are on different sides of the waveguide ( simple configuration), while in the second, they are alternated periodically across the waveguide sides ( interdigitated configuration). Both simulations and experiments show that the generation efficiency is increased by 10 times comparing the interdigitated and simple configurations. The effective second-order susceptibility modulation obtained at a reverse bias voltage of 3.5 V is Δ χ e f f , S ( 2 ) ≃ 0.14 p m / V for the simple configuration and Δ χ e f f , I ( 2 ) ≃ 0.64 p m / V for the interdigitated one.