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What is CLadding?
In photonics and fiber optics, cladding is the low-refractive-index layer of material that surrounds the central core of an optical fiber. Its primary purpose is to confine light within the core via total internal reflection, preventing the optical signal from escaping and reducing transmission loss over long distances.
By acting as a protective and functional barrier, cladding ensures that light pulses remain trapped and guided smoothly along the fiber path.
HOW Cladding Works
Establising index contrast
The cladding is intentionally engineered from a material (typically glass or plastic) with a lower refractive index than the fiber's core. This precise difference in optical density is what makes guided light transmission possible.
Enabling total internal reflection
When light signals travel through the core and strike the boundary between the core and the cladding at a shallow angle, the lower refractive index of the cladding forces the light to bounce back into the core. This phenomenon, known as total internal reflection, keeps the signal moving forward without escaping.
Isolating the optical signal
Beyond its optical properties, the cladding acts as a physical barrier. It prevents external contaminants, moisture, and surface scratches from interfering with the light path, while also isolating the signal from absorbing energy from outer protective coatings.
