Multiple core optical fibre

Abstract

A multicore optical fibre includes a microstructured cladding material formed from a plurality of cladding elements arranged in an array and each cladding element comprising at least two different materials each having different refractive indices, and a plurality of core elements formed within interstitial regions between adjacent cladding elements. A fibre so formed may have a large number of cores per unit cross-sectional area as compared with prior art fibres, and thus allows the fibre to have relatively short distances between adjacent cores for a given required inter-core isolation. A fibre so formed has utility in many areas requiring high core density, such as inter-chip optical communication, or optical communication between circuit boards.

1 - 22 . (canceled) 
   
   
       23 . A multicore optical fibre comprised of a plurality of cladding elements forming a regular, periodic cladding array, each cladding element having a higher index region and a lower index region, with interstitial regions formed between said cladding elements, wherein core element material is inserted into a plurality of the interstitial regions during a manufacturing stage so as to form a plurality of core regions, each core in the fibre being substantially surrounded by the lower index region of the cladding elements, such that the regularity of the cladding array is not affected. 
   
   
       24 . A multicore fibre as claimed in  claim 23  wherein each cladding element comprises an inner and an outer region, with the inner region having a different refractive index to the outer region. 
   
   
       25 . A multicore fibre as claimed in  claim 24  wherein the inner region comprises one of a gas, a vacuum and a liquid. 
   
   
       26 . A multicore fibre as claimed in  claim 24  wherein the outer region of each cladding element has a higher refractive index than the inner region. 
   
   
       27 . A multicore fibre as claimed in  claim 23  wherein the core material has a refractive index substantially similar to that of the cladding material having a higher refractive index. 
   
   
       28 . A multicore fibre as claimed in  claim 23  wherein the cladding elements comprise cylindrical tubes. 
   
   
       29 . A multicore fibre as claimed in  claim 23  wherein at least one core element contains a dopant. 
   
   
       30 . A multicore fibre as claimed in  claim 23  wherein the cladding elements are of different overall dimensions in one transverse axis as compared to another transverse axis. 
   
   
       31 . A multicore fibre as claimed in  claim 30  wherein the fibre is birefringent. 
   
   
       32 . A multicore fibre as claimed in  claim 23  wherein certain cladding elements are arranged to have different relative quantities of materials as compared to other cladding elements. 
   
   
       33 . A multicore fibre as claimed in  claim 23  wherein at least one core element is of a different size to an adjacent core element. 
   
   
       34 . A multicore fibre as claimed in  claim 23  wherein a coupling coefficient between two adjacent cores is arranged to be not greater than a required design value. 
   
   
       35 . A multicore fibre as claimed in  claim 23  wherein a coupling coefficient between two adjacent cores is arranged to be not less than a required design value. 
   
   
       36 . A multicore fibre as claimed in  claim 23  wherein at least one core element comprises a single mode fibre. 
   
   
       37 . A multicore fibre as claimed in  claim 23  wherein the fibre is adapted to taper in diameter along its length.