Independent dual-single sideband lower-IF RF receiver based on a single photodetector

The two sidebands of the independent dual-single-sideband (dual-SSB) signal can carry different information, which achieves higher spectral efficiency and system capacity. However, the receiver divides the signal into two channels, so a pair of optical bandpass filters (OBPFs) and photodetectors (PDs) are generally required to select and detect an independent dual-SSB signal. To reduce the complexity and cost of the receiver, we propose an independent dual-SSB lower intermediate frequency (IF) radio frequency (RF) signal detection scheme based on a single PD combined with conventional digital signal processing (DSP). A theoretical analysis is presented and validated by a simulation. The left sideband (LSB) and the right sideband (RSB) are quadrature phase-shift keying (QPSK) modulated. After 50-km standard single-mode fiber (SSMF) transmission, a 10-Gbps 16QAM signal is synthesized from 2 × 5-Gbps dual-SSB QPSK and the independent dual-SSB is extracted by DSP. The bit error rate (BER) of the dual-SSB (LSB and RSB) is below the hard-decision forward-error-correction (HD-FEC) threshold of 3.8 × 10^-3.