Fig. 1. Generation principle of photonics assisted terahertz QPSK based on OOK modulation

Fig. 2. Optical spectra. (a) Optical carrier; (b) DP-MZM output; (c) PBC output; (d) PD output

Fig. 3. Constellations of QPSK signals passing through DSP. (a) 80 GHz; (b) 240 GHz; (c) 400 GHz

Fig. 4. Relationship between BER of QPSK signal and OSNR

Fig. 5. Relationship between BER of QPSK signal and transmission distance

Fig. 6. Relationship between BER of QPSK signal and input power of PD

Fig. 7. Relationship between BER of QPSK signal and baud rate

Fig. 8. Relationship between BER and extinction ratio

Fig. 9. Relationship between BER and orthogonality deviation