Fig. 5: Eight-mode data transmission of 28-GBaud 16-QAM signals.
From: Metamaterial-enabled arbitrary on-chip spatial mode manipulation
a Microscope image of the fabricated 8-channel MDM PIC. b SEM image of the two-stage multiplexer for the TE6 mode, consisting of a metamaterial TE0-TE5 mode operator and a TE5-TE6 ADC. c Measured summed modal crosstalk from the other seven channels for each output port. d Experimental setup for high-speed transmission of 28-GBaud 16-QAM signals. TLS tunable laser source, PC polarization controller, DAC digital-analog converter, EA electronic amplifier, IQM in-phase/quadrature modulator, EDFA erbium-doped fiber amplifier, OBPF optical band pass filter, WS wave shaper, AOM acousto-optical modulator, DL delay line, VOA variable optical attenuator, PBC polarization beam combiner, CR coherent receiver, DSO digital storage oscilloscope. e Measured bit error rates (BERs) for eight channels. f Corresponding recovered constellation diagrams for eight modes
