Broadband photonic lantern mode multiplexers based on multilayer polymer waveguides

We demonstrate broadband photonic lantern mode multiplexers based on multilayer polymer waveguides to achieve spatial multiplexing of the LP₀₁, LP_11a, and LP_11b modes. The devices are thermally stable and polarization-insensitive. The crosstalk in a typical fabricated device varies from -11 to -22 dB, depending on the input mode and the output core. Our mode multiplexers could find applications in mode-division-multiplexing transmission systems.