Fig. 4: Free-space transmission results using the Standard-QCL.
a BER results with the QCD at the receiver. The BER are measured as a function of the QCL bias current for different modulation formats, namely, NRZ, PAM4, and PAM6. Two FEC code thresholds, i.e., 6.25% overhead HD-FEC of 4.5 × 10−3 BER, and 20% overhead SD-FEC of 2 × 10−2 BER, are shown to benchmark the performance. b Selected eye diagrams of the received signal detected with the QCD, measured at the highest bias current after receiver equalization. The distribution of recovered symbols at the decision points are shown in the histograms. c BER results with the QWIP at the receiver. d Selected eye diagrams and symbol distribution histograms of the signals detected with the QWIP, measured at the highest bias current after receiver equalization.
