Polymeric waveguides using oxidized porous silicon cladding for optical amplification

Abstract: We report on a new hybrid approach to realize optical slab waveguides for optical amplification purposes. The structure consists of a dye-doped polymer core (PMMA) deposited over an oxidized porous silicon (PS) cladding layer formed on a silicon wafer. The very low refractive index (n =1.16) achievable in the cladding allows obtaining monomodal behavior with high confinement factors (Γ TE =96%) even for very thin cores (400nm). Optically excited guided luminescence shows stimulated emission, strong line narrowing and a clear threshold and superlinear behavior with pump energy. By means of the variable stripe length (VSL) technique, values of net optical gain up to 113dB/cm (constant over 3mm) and absolute amplification values up to 34dB have been measured at 694nm when pumping with 80mJ/cm2 energy pulses. These results validate the use of oxidized PS as a cladding layer in silicon photonics. [Copyright &y& Elsevier]