Patent ID: 8089619
Filing Date: 2012-01-03
Classification: C03B

Abstract:
1. A process for manufacturing a microstructured optical fibre comprising a void-containing region, the fibre having an outer surface defining an outer diameter, comprising the steps of: drawing a microstructured optical fibre along a longitudinal direction from a heated preform, wherein the optical fibre is continuously advanced along the longitudinal direction; directing a radiation beam at a longitudinal position in the longitudinal direction of the optical fibre so as to produce an interference pattern; detecting the interference pattern and producing at least one electrical detection signal corresponding to the interference pattern and comprising a plurality of signal wave fringe cycles; feeding the at least one detection signal into a first counter circuit; determining a first number of interference fringe increments in the plurality of signal wave fringe cycles of the at least one detection signal by using the first counter circuit; determining the outer diameter of the optical fibre; and controlling the microstructure of the optical fibre during advancement of the optical fibre, wherein the step of controlling comprises at least one step selected from: (a) controlling the first number of interference fringe increments within a reference number range of reference numbers of interference fringe increments, the reference numbers being smaller than a second number of interference fringe increments related to the outer diameter of the microstructured optical fibre by a conversion factor; and (b) calculating a microstructure length value by multiplying the first number of interference fringe increments by a conversion factor and controlling the value of the microstructure length value within a reference length range of reference microstructure length values, the reference microstructure length values being smaller than the outer diameter of the microstructured optical fibre.