Fig. 1. Proposed frequency-octupled phase-coded signal generation system.

Fig. 2. Output optical spectra of (a) the integrated modulator, and the upper and bottom QPSK modulators and (b) the Pol.

Fig. 3. Waveforms of the 2 Gbit/s, 21.92 GHz phase-coded signal when the voltage of the coding signal is (a) 1.5 and (b) 2 V, (c) the extracted phase shifts from (a) and (b).

Fig. 4. (a) Waveform of the 5 Gbit/s, 21.92 GHz phase-coded signal, (b) the extracted phase shift, and (c) the autocorrelation. Inset: zoom-in on the peak of the autocorrelation.

Fig. 5. Waveforms of the 2 Gbit/s phase-coded signal with frequency of (a) 16.48 and (b) 29.76 GHz, (c) the extracted phase shifts from (a) and (b).