|<<< | >>> | Feedback| Definition: a kind of long and thin
optical waveguides which can be bent to some degree (British
spelling: fibres) Optical fibers are a kind of waveguides, which
are usually made of some kind of glass, can potentially be very
long (hundreds of kilometers), and are – in contrast to other
waveguides – fairly flexible. The most commonly used glass is
silica (quartz glass, amorphous silicon dioxide = SiO2), either
in pure form or with some dopants. Silica is so widely used
because of its outstanding properties, in particular its
potential for extremely low propagation losses (realized with
ultrapure material) and its amazingly high mechanical strength
against pulling and even bending (provided that the surfaces are
well prepared). Most fibers used in laser optics have a core
with a refractive index which is somewhat higher than that of
the surrounding medium (called the cladding). The simplest case
is that of a step-index fiber, where the refractive index is
constant within the core and wit