Optical fibers having cores with different propagation constants, and methods of manufacturing same

A method for manufacturing a multi-core fiber comprising:

• forming a plurality of canes including a core material and a cladding material around the core material;
• coupling the plurality of canes to provide a preform;
• and
• drawing the multi-core fiber from the preform to provide a multi-core fiber having a plurality of cores having different associated propagation constants, and wherein a separation between adjacent ones of the plurality of cores is about 70 microns to about 125 microns.

A method for manufacturing a multi-core fiber comprising:

• forming a plurality of canes including a core material and a cladding material around the core material;
• separately drawing each of the plurality of canes to provide a plurality of single core fiber elements each including a core and a cladding layer, the cores having different associated propagation constants, the different propagation constants being provided by a difference between core deltas of at least adjacent ones of the cores;
• and
• coupling the plurality of single core fiber elements to provide a multi-core fiber having a plurality of cores.

A wavelength division multiplexing (WDM) system comprising:

• an optical input device that receives data for transmission from at least one data source;
• a multi-core optical fiber coupled to the input device, the multi-core optical fiber having a first core that has a first associated mean propagation constant and an adjacent second core that has a second associated mean propagation constant different from the first mean propagation constant and wherein a separation between the first core and the second core is about 70 microns to about 125 microns;
• and
• an optical output device configured to couple the multi-core optical fiber to a destination device.