Abstract

Single-crystal silicon is a promising new material for integrated-optical components, both active and passive, that operate at λ = 1.3 and 1.6 µm. According to the data of Fan et al.¹ and Swimm,² high-purity monocrystal silicon is highly transparent at the 1.3- and 1.55- µm fiber-optical communications wavelengths. (The absorption spectrum is shown in Fig. 1.) The absorption coefficient can be as low as 10⁻³ cm⁻¹ when ρ = 10⁴ Ω cm. Thus, in theory, silicon is suitable for low-loss waveguiding at these wavelengths. Experimentally, we have examined the conditions of epitaxy, ion implantation, diffusion, annealing, and doping that are appropriate for making guiding layers. It is important to control the morphology and crystallinity of the guiding layer because optical scattering and absorption will increase if grain boundaries and lattice defects are present. Thus polycrystalline-Si and amorphous-Si are less desirable for guiding than crystalline-Si. In recent years, epitaxial growth techniques for single-crystal Si have been perfected for VLSI and discrete electronic device applications.

© 1986 Optical Society of America