Fig. 1. Principle diagrams of six-fold frequency vector millimeter wave signal generation. (a) Output simple spectrum of ECL; (b) simple spectrum of RF; (c) output simple spectrum of IM; (d) output simple spectrum of HNL-DSF; (e) output simple spectrum of filter; (f) output simple spectrum of PD

Fig. 2. Original and precoding QPSK signal constellation for signal at the transmitter. (a) Original QPSK signal constellation diagram; (b) QPSK signal constellation diagram after balanced precoding

Fig. 3. The first kind of Bessel function curves

Fig. 4. Experimental setup and photos of the generation and transmission of six-fold frequency vector millimeter wave system. (a) Transmission setup; (b) photo of the transmission system; (c) photo of the transceiver ends; (d) photo of the receiver end

Fig. 5. Optical spectra of the optical signals after optical devices. (a) Output spectrum of MZM; (b) output spectrum of IL1; (c) output spectrum of HNL-DSF; (d) output spectrum of IL2; (e) output spectrum of EDFA

Fig. 6. Spectrum of the IF signal

Fig. 7. BER versus input power into PD for QPSK signal with 72 GHz, 2 GBaud

Fig. 8. Constellations for QPSK signal after DSP at the receiver. (a) Received signal; (b) signal after two times down-sample; (c) signal after CMA and post-equalization; (d) signal after frequency offset estimation; (e) signal after carrier phase offset estimation

Fig. 9. Required optical power at BER of 3.8×10^-3 versus fiber length for QPSK signal with 72 GHz, 2 GBaud

Fig. 10. BER versus baud rate of QPSK signal with 72 GHz