Polarization dependence is a major factor of consideration in the design of optical waveguide devices for applications in optical fiber transmission systems. In many cases, the polarization-dependence problem can be solved by using waveguides with zero modal birefringence. In this paper, theoretical results are presented to show how zero- birefringence waveguides can be designed from various waveguide geometries. The waveguides considered in this paper include strip waveguides, rib waveguides, waveguides, strip-loaded waveguides, and multiple-quantum-well waveguides, which are of particular importance in the construction of semiconductor-based photonic integrated circuits. The design of polarization-insensitive directional couplers with rib waveguides is also discussed.