Optical fibers are examples of "dielectric waveguides". Transitions between conductive lines and dielectric lines or waveguides are more complex. The cavities of laser diodes are frequently constructed as rectangular optical waveguides. At these wavelengths dielectric waveguides can have lower losses than metal waveguides. Their main technological application is as optical waveguides in both planar and fiber form. Standing waves are also observed in optical media such as optical waveguides and optical cavities. Instead, fiber optics, which are a form of dielectric waveguides, can be used. The radiating elements are circularly-polarized, slotted waveguides. There are two technologies used in augmented reality&colon; diffractive waveguides and reflective waveguides. At Bell Labs in 1931 he resumed work in dielectric waveguides. Two types of optical waveguides are in common use. One of the methods for constructing such waveguides utilizes photorefractive effect in transparent materials. It is an excellent material for manufacture of optical waveguides. Beam propagation method (BPM) can solve for the power flow in waveguides. The formation of such waveguides leads to a breakup of the laser beam.