Technique for controlling the internal rotation of principal axes in the fabrication of birefringent fibers

The fabrication of a polarization-maintaining fiber in which the internal rotation of the principal birefringent axes was monitored and controlled to a rate of less than 0.1 degrees /cm is discussed. This represents an order of magnitude improvement over the lowest rotation rate observed in commercial fibers. The technique is based on a novel method of interpreting the backscattered power from a-side illuminated birefringent fiber to determine the internal orientation of the strain inducing axes.<
>