Patent ID: 11964899
Assignee: UNIVERSITY OF SOUTHAMPTON
Field: Other special machines (Mechanical engineering)
Classification: CPC C  G | IPC C  G

Claim 25:
26. A method of making an optical fibre preform comprising:
providing a hollow outer tube of glass;
providing a hollow primary capillary tube of glass with an outer diameter smaller than an inner diameter of the outer tube;
providing a hollow secondary capillary tube of glass with an outer diameter smaller than an inner diameter of the primary capillary tube;
positioning the primary capillary tube inside the outer tube such that an outer surface of the primary capillary tube lies against an inner surface of the outer tube along a contact line parallel to the longitudinal axes of the primary capillary tube and the outer tube;
positioning the secondary capillary tube inside the primary capillary tube such that an outer surface of the secondary capillary tube lies against an inner surface of the primary capillary tube in radial alignment with the said contact line;
supporting the secondary capillary tube, by a stand in contact with the secondary capillary tube, in a horizontal orientation so that the capillary tubes orient themselves, under gravity, along the contact line along the apex of the outer tube, primary capillary tube, and secondary capillary tube; and
bonding the primary capillary tube into its position inside the outer tube by directing the laser beam to be incident onto an outer surface of the outer tube or the inner surface of the primary capillary tube at one or more locations aligned with the contact line.