POROUS SILICON MULTILAYER OPTICAL WAVE-GUIDES

Optical waveguiding is demonstrated in porous silicon multilayers. Dep th variations in porosity, and therefore refractive index, are achieve d by switching between high and low current densities during the anodi c etch process. Planar waveguiding has been demonstrated at lambda = 1 .28 pm. The wavelength range has been extended to the visible (lambda = 0.6328 mu m) by oxidising the samples to produce layered porous oxid e structures. Two-dimensional strip-loaded waveguides have been produc ed, for both the visible and infrared, by etching into each top layer through a pre-deposited photolithographically-defined mask.