Method and apparatus relating to optical fibres
AssigneeCrystal Fibre A/S
InventorsTimothy Adams Birks, Jonathan Cave Knight, Philip St John Russell, Brian Joseph Mangan
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Abstract
A method of joining a first optical fibre (110) to a second optical fibre (130) comprises the steps of: (i) providing a preform element (10) comprising material defining a primary elongate cavity (40); (ii) inserting the first optical fibre (110) into the primary cavity (40) to form a preform (125); and (iii) drawing the second optical fibre (130) from the preform (125); wherein, the second optical fibre (130) includes a core region comprising material that has been drawn from the first optical fibre (110).
Claims69
A method of joining a first optical fibre to a second optical fibre, the method comprising the steps of:
- (i) providing a preform element comprising material defining a primary elongate cavity;
- (ii) inserting the first optical fibre into the primary cavity to form a preform;
- and (iii) drawing the second optical fibre from the preform;
- wherein, the second optical fibre includes a core region comprising material that has been drawn from the first optical fibre.
A method as claimed in any preceding claim, in which the material of which the preform element is comprised is undoped.
A method as claimed in any preceding claim, in which the primary cavity has a smallest transverse dimension of at least 100 microns.
A method as claimed in any preceding claim, in which a plurality of first optical fibres are inserted into the primary cavity.
A method as claimed in any preceding claim, in which the preform element has a plurality of primary cavities into each of which a first optical fibre is inserted.
A method as claimed in any preceding claim, in which the preform includes a secondary elongate cavity that does not receive an optical fibre.
A method as claimed in any preceding claim, in which the secondary cavity is at most 500 microns in its largest transverse dimension.
A method as claimed in any preceding claim, in which the preform element comprises a plurality of solid, elongate cylinders, which are drawn to form part of a cladding region of the second fibre.
A method as claimed any preceding claim, in which the preform element is formed by stacking a plurality of elements.
A method as claimed in any preceding claim, in which the first fibre is a standard fibre.
A method as claimed in any preceding claim, in which the preform element is enclosed in an outer jacket.
A method as claimed in any preceding claim, in which the second fibre is drawn in a fibre drawing tower.
A method as claimed in any preceding claim, in which a hole is prevented from forming in the second fibre by maintaining differential gas pressures in holes during drawing.
A method as claimed in any preceding claim in which a core is provided in the preform, the core having a diameter sufficiently different from the diameter of the core of the first optical fibre that the cores couple into different transverse modes of the second optical fibre, the core, the first optical fibre and the preform being arranged such that light propagating in the first optical fibre will excite a higher-order mode in the second optical fibre.
An optical device comprising a first optical fibre and a second optical fibre having a core region and a cladding region, wherein the core region of the second optical fibre comprises material that has been drawn from the first optical fibre.
An optical fibre transformation device, comprising a length of a preform element including a length of a first fibre inside a first hole, the other end comprising a second fibre that is a photonic crystal fibre, and a gradual transition from one structure to the other in between.
A preform element comprising a primary elongate cavity large enough to receive a first optical fibre and a secondary elongate cavity, such that, when an assembly of the preform element and a first optical fibre is drawn down in size a second optical fibre is formed, the second fibre being a photonic crystal fibre with a core incorporating the first fibre and a cladding incorporating the secondary elongate cavity.
Dependencies are inferred from the claim text.