Optical amplifier for space-division multiplexing

An apparatus, comprising:

• an input port configured to end-connect to a first optical fiber transmission line;
• an output port configured to end-connect to a second optical fiber transmission line;
• a first doped multi-core optical fiber having a first plurality of optical waveguide cores, each configured to amplify, using a first optical pump beam, a respective portion of optical power received through the input port to generate a respective amplified portion of the optical power, wherein the first doped multi-core optical fiber is configured to direct the amplified portions of the optical power generated by different ones of the first plurality of optical waveguide cores toward the output port;
• and
• a first optical coupler coupled between the input port and the first doped multi-core optical fiber, wherein:
• the first optical coupler comprises a second plurality of optical waveguide cores, each configured to guide the respective portion of the optical power received through the input port toward the respective one of the first plurality of optical waveguide cores;
• and
• a spatial arrangement of the second plurality of optical waveguide cores at an input end of the first optical coupler is different from a spatial arrangement of the second plurality of optical waveguide cores at an output end of the first optical coupler.

An apparatus comprising:

• an input port configured to end-connect to a first optical transmission line;
• an output port configured to end-connect to a second optical transmission line;
• a first doped multi-core optical fiber having a first plurality of cores, each configured to amplify, using a first optical pump beam, a respective portion of optical power received through the input port to generate a respective amplified portion of the optical power, wherein the first doped multi-core optical fiber is configured to direct the amplified portions of the optical power generated by different ones of the first plurality of cores toward the output port;
• and
• a first optical coupler coupled between the first doped multi-core optical fiber and the output port, wherein:
• the first optical coupler comprises a second plurality of cores, each configured to guide the respective one of the amplified portions of the optical power generated by different ones of the first plurality of cores toward the output port;
• and
• a spatial arrangement of the second plurality of cores at an input end of the first optical coupler is different from a spatial arrangement of the second plurality of cores at an output end of the first optical coupler.