A apodized chiral fiber grating consists of a chiral fiber with a variable
effective grating strength along different regions of its length, such
that the effective grating strength gradually increases from one end of
the chiral fiber until a peak effective grating strength is reached and
then gradually decreases at the same rate towards the other end of the
fiber. Optionally, the effective grating strength remains stable for a
portion of the fiber before decreasing. Other forms of grating strength
variations in different regions of the chiral fiber are also contemplated.
The effective grating strength variation produces an apodized chiral fiber
that possesses desirable characteristics that greatly reduce or eliminate
the sidelobes in the fiber's spectral response. The effective grating
strength is varied by modulating the pitch of the apodized chiral fiber
along different regions of its length in accordance with a mathematical
expression, such as for example: linear, polynomial, sinusoidal or
quasi-sinusoidal function. Advantageously, the inventive apodized chiral
fiber is customizable to any application by selectively controlling the
pitch variation along the different regions.
