Experimental Demonstration of DFT-Precoded Guard-Band OSSB-OFDM Signal Reception with ADC Undersampling Technique

Guard-band optical single-side-band orthogonal frequency-division multiplexing (GB-OSSB-OFDM) is a good solution to achieve long-haul transmission as well as high receiver sensitivity. A low-complexity receiver with ADC undersampling technique is experimentally demonstrated in a GB-OSSB-OFDM transmission system. The principle of the proposed ADC undersampling technique and the constraint conditions on the use of such a technique are presented and discussed in detail. Besides, the discrete Fourier transform (DFT) precoding technique is also applied to reduce the peak-to-average power ratio (PAPR) of the baseband GB-OFDM signal as well as improve bit error rate (BER) performance. By using the DFT precoding technique, it exhibits that the PAPR of the GB-OFDM signal can be reduced by about 6 dB at the complementary cumulative distribution function (CCDF) of $1\times 10^{-3}$ . After 100 km standard single-mode fiber (SSMF) transmission, the results show that the ADC undersampled low-complexity receiver has similar BER performance with the conventional oversampled GB-OFDM receiver. At the BER of $3.8\times 10^{-3}$ , the receiver sensitivity in terms of received optical power can be improved by about 2 dB with the DFT precoding technique.