Backward Second Harmonic Generation in Silicon waveguide

The first report on backward second harmonic generation (SHG) in silicon waveguides is presented in this paper. Second-order nonlinearity, chi((2)), in silicon is realized by using large chi((3)) of silicon and large DC electric field obtained in an embedded reverse-biased pin diode via four-wave mixing, an effect which is known as electric filed induced SHG. The considered pin diode has periodic structure along the waveguide to achieve quasi-phase matching technique. An efficiency up to P-2 omega/P-omega= 40 % is predicted which is 20-fold of all previously reported values, based on the best of our knowledge. Besides, the generated power of the second harmonic frequency can he controlled by applying voltage and even be more efficient with upper limit of similar to 53%.