The present invention provides methods for manufacturing microstructured optical
fibers having an arbitrary core size and shape. According to one embodiment of
the invention, a method of fabricating a photonic band gap fiber includes the steps
of forming an assembly of stacked elongate elements, the assembly including a first
set of elongate elements, the first set of elongate elements defining and surrounding
a core volume, and a second set of elongate elements surrounding the first set
of elongate elements, wherein the core volume defined by the first set of elongate
elements has a shape that is not essentially an integer multiple of the external
shape of the elongate elements of the second set of elongate elements; including
the assembly in a photonic band gap fiber preform; and drawing the photonic band
gap fiber preform into the photonic band gap fiber.