Optical waveguides are structures that guide light waves along a specific path, typically made from materials like glass or plastic. They work by using the principle of total internal reflection, allowing light to be confined within the waveguide and transmitted over long distances with minimal loss. Common applications include fiber optic communication and sensors. These waveguides can vary in shape and size, including fiber optics, planar waveguides, and photonic crystal waveguides. They are essential in modern telecommunications, enabling high-speed data transmission and improving the efficiency of optical systems.