In fiber optics
, a quadruply clad fiber
is a single-mode optical fiber
that has four claddings. Each cladding
has a refractive index
lower than that of the core
. With respect to one another, their relative refractive indices are, in order of distance from the core: lowest, highest, lower, higher.
A quadruply clad fiber has the advantage of very low macrobending losses. It also has two zero-dispersion points, and moderately low dispersion over a wider wavelength range than a singly clad fiber or a doubly clad fiber.