Method for Manufacturing LMA Optical Preforms and Fibers
OwnerValentin P. Gapontsev, Volodia Sergueev +1inventors
InventorsValentin P. Gapontsev, Volodia Sergueev, Nikolai Platonov
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Abstract
A method of producing a large mode area optical preform includes selecting a preexisting rod and at least one preexisting outer tube. The rod and tube are selected so that a difference between respective indices of refraction is uniform and lies within the desired range, and a ratio between respective rod and tube diameters is within the desired range after the rod is inserted into the tube and both are thermally treated. The predetermined ranges are selected to provide mass production of a large mode area fiber with the desired physical and geometrical characteristics.
Claims20
A process for mass producing an LMA optical preform with a predetermined and uniform difference Δn between indices of refraction of respective core and cladding of the optical fiber and a predetermined range ΔD of ratios between diameters of respective cladding and core, the method comprising the steps of:
- providing a preexisting elongated rod having a substantially uniform core index of refraction over a length of the rod, the preexisting rod having a rod diameter Dc;
- providing at least one preexisting tube having:
- a tube diameter Dcl greater than the rod diameter, and
- a tube index of refraction smaller than the rod index, a difference between the indices of the respective preexisting rod and one tube being substantially equal to the predetermined Δn;
- disposing the elongated rod within the tube to provide a rod-in-tube assembly;
- and
- thermally treating the rode-in-tube assembly so that the tube collapses onto the rod while adjusting the rod and tube diameters so that a ratio Dcl to Dc is substantially within the predetermined range of ratios ΔD, thereby forming the LMA optical preform.
A large mode area (LMA) optical preform comprising:
- a preexisting rod having a rod diameter Dc and a rod index of refraction nc;
- and
- at least one preexisting tube disposed around the preexisting rod and coupled thereto, the one preexisting tube being provided with a tube diameter and a tube index of refraction, the rod and tube indexes being selected so that a difference therebetween is uniform and lies within a predetermined range Δn, the preexisting rod and one tube being heated to set in the LMA preform with the rod and tube diameters reduced so that a ratio therebetween lies within a predetermined range ΔD.
Dependencies are inferred from the claim text.