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What is a Step-Index Fiber?
A Step-index fiber is an optical fiber in which the refractive index remains constant throughout the core and changes abruptly at the boundary between the core and cladding. This simple refractive index profile determines how light is guided through the fiber.
Step-index fibers can be designed as single-mode or multimode fibers and are used in applications requiring specific combinations of optical performance, power handling, and mechanical properties.
HOW a Step-Index Fiber Works
A step-index fiber guides light through an abrupt change in refractive index between the core and cladding. The resulting index profile determines the fiber's numerical aperture and modal propagation characteristics.
Constant core index
The core has a relatively uniform refractive index across its diameter.
Abrupt index transition
At the core-cladding boundary, the refractive index decreases suddenly, creating the optical guiding structure.
Mode propagation
Light remains guided within the core through total internal reflection, with the number of supported modes depending on parameters such as core diameter, numerical aperture, and operating wavelength.
