Optical waveguide

An optical waveguide is a physical structure that guides light along a defined path thanks to total internal reflection, resulting from the difference in refractive index between the core and the surrounding cladding.

How does an optical waveguide work?

The waveguide core has a higher refractive index than the surrounding material, so light striking at the appropriate angle undergoes total internal reflection and stays trapped inside the structure. The number and shape of the modes a waveguide can guide depends on its dimensions, the refractive-index contrast, and the wavelength of the light.

Applications

Optical waveguides are a fundamental element of photonic integrated circuits (PICs), optical fibers in telecommunications, fiber-optic sensors, and integrated optics devices such as modulators and couplers.

Related terms

Mode solver

TIR (total internal reflection)

BPM