High-power multiplexer and demultiplexer for hollow core fiber dense wavelength-division multiplexing (DWDM) applications

A high-power optical transport multiplexer/demultiplexer (“mux/demux”) node, comprising:

• a first hollow core optical fiber interface configured to couple with a first free-space optical fiber cable;
• a set of second hollow core optical fiber interfaces configured to couple with a corresponding set of second free-space optical fiber cables;
• a diffraction grating configured either to diffract a single incoming optical signal having multiple wavelengths into a plurality of outgoing optical signals based on different wavelengths or to diffract a plurality of incoming optical signals having different wavelengths into a single outgoing optical signal having multiple wavelengths, wherein the single incoming optical signal contains a multiplexed combination or optical signals having different polarizations, wherein the plurality of incoming optical signals has different polarizations;
• a polarization diversity optic configured either to separate the single incoming optical signal into different optical signals based on the different polarizations or to combine the plurality of optical signals into the single outgoing optical signal;
• a three-dimensional (“3D”) printed phase mask having an incident surface including a plurality of reflective features configured to reflect a corresponding plurality of optical signals having different wavelengths at different optical path lengths to provide the reflected corresponding plurality of optical signals with different phases;
• one or more collimating lenses configured to collimate optical signals onto or from the diffraction grating;
• and
• one or more focusing lenses configured to focus optical signals onto or from the 3D printed phase mask.