ABSTRACT
The loss requirements for planar waveguides on substrates with wafer-size (about 30 cm) to chip-size (about 1 cm) dimensions are less stringent. This chapter focuses on the mode characteristics and single-mode conditions for the silicon-on-insulator (SOI) waveguides, including the slab, strip, and rib waveguides, and then continues on the loss and polarization dependence in the SOI waveguide. The material properties, structure, and dimensions of an optical waveguide are the boundary conditions for solving Maxwell’s equations. To solve Maxwell’s equations in the optical waveguide, we will get multiple different sets of eigenvalues and their corresponding eigenfunctions. The slab waveguide consists of a guiding layer (or core layer), a substrate layer, and a cover layer or cladding layer. Considering the most popular silicon waveguide system, that is, the SOI platform, the three layers of the slab waveguide are air, silicon, and silica, with the corresponding refractive indices.
