Waveguide (optics)
（重定向自Rectangular waveguide）
![A dielectric slab waveguide consists of three dielectric layers with different refractive indices.](/Images/godic/202502/06/Slab_waveguide_1.svg3827.png")
![Optical waveguides formed in pure silica glass as a result of an accumulated self-focusing effect with 193 nm laser irradiation. Pictured using transmission microscopy with collimated illumination.](/Images/godic/202502/06/SF_waveguides3827.jpg")
![The propagation of light through a multi-mode optical fiber.](/Images/godic/202502/06/Optical-fibre.svg3827.png")
An optical waveguide is a physical structure that guides electromagnetic waves in the optical spectrum. Common types of optical waveguides include optical fiber and rectangular waveguides.
Optical waveguides are used as components in integrated optical circuits or as the transmission medium in local and long haul optical communication systems.