casting [9], injection molding, and drilling. The materials used ranged from silica
to compound glasses, chalcogenide glasses, and polymers [10].
The most widely used technique is stacking of circular capillaries. Typically,
meter-length capillaries with an outer diameter of 1 mm are drawn from a
starting tube of high-purity synthetic silica with a diameter of 20 mm. The
inner/outer diameter of the starting tube, which typically lies in the range from
0.3 up to beyond 0.9, largely determines the d/L (hole diameter to spacing ratio)
value in the drawn fiber. The capillaries are stacked horizontally, in a suitably
shaped jig, to form the desired crystalline arrangement. The stack is bound with
wire before being inserted into a jacketing tube, and