Element for a preform, a fiber production method and an optical fiber drawn from the preform

A method of producing a microstructured fiber, the method comprising:

• assembling a preform assembly, the preform assembly comprising:
• a preform center element;
• a preform ring element;
• wherein the preform ring element is a hollow cane comprising a ring-wall background material that defines a ring-wall, wherein the hollow cane has a cane-length, a first cane-end, and a second cane-end, wherein the hollow cane further has a first inner surface with an average inner diameter, and a first outer surface with an average outer diameter, such that a distance from the average inner diameter to the average outer diameter defines a thickness of the ring-wall, wherein the ring-wall background material comprises a first plurality of longitudinal holes along the cane-length;
• wherein the preform center element comprises a center-structure that has a center-length, a first center-end, and a second center-end, wherein the center structure comprises a second outer surface with an average cross-sectional diameter less than the average inner diameter of the preform ring element resulting in one or more gaps between the second outer surface of the preform center element and the first inner surface of the preform ring element;
• and
• at least one first slot in the preform ring element that intersects at least one of the first plurality of longitudinal holes and that is configured to transfer fluid into the intersected at least one of the first plurality of longitudinal holes;
• and
• transferring fluid into the at least one of the first plurality of longitudinal holes by controlling a first pressure of the fluid;
• and
• drawing the preform assembly to the microstructured fiber.