Patent ID: 8903211

Claim:
An optical fiber coupler for connecting a transmission multicore optical fiber (TMCF) with an amplifier multicore optical fiber (AMCF) and a plurality of optical pump fibers, the coupler comprising: a plurality of signal cores extending between a multicore input endface and a coupler output endface, wherein the multicore input endface is configured to be connectable to the TMCF such that each signal core carries signal light at a signal wavelength from a respective TMCF core; and a plurality of pump cores, each extending between a pump input and the coupler output endface, wherein each pump input is configured to be connectable to a pump input fiber such that each pump core carries pump light at a pump wavelength from a respective pump input fiber, wherein the pump wavelength is different from the signal wavelength, wherein each pump core is paired with a corresponding signal core to form a core pair that is adiabatically tapered along an adiabatically tapered coupler section, such that signal light carried by the signal core is combined with pump light carried by the pump core along the adiabatically tapered section, and wherein the coupler output endface is configured to be connectable to the AMCF such that the combined light output of each core pair is provided as an input to a respective AMCF core.