A cost-efficient dual-band transmission scheme based on return-to-zero (RTZ)-mode digital-to-analog converter (DAC) and sub-Nyquist sampling analog-to-digital converter (ADC) is proposed in this paper. The scheme can increase the data rate and meanwhile halve the required sampling rate of the DAC/ADC in optical intensity modulation direct detection (IMDD) transmission system. Based on this scheme, we experimentally demonstrate a dual-band discrete Fourier transformation spread (DFT-S) OFDM intensity modulation direct detection (IMDD) system. Although the sampling rate of the DAC and ADC used in the receiver is only 5-GSa/s and there is no mixer and oscillator at the transmitter and receiver side, 22-km standard single-mode fiber (SSMF) transmission with up to 26.33-Gb/s data rate is successfully realized. The experimental results show that in the system, the first sub-band transmission based on 128-QAM mapping can achieve a bit error rate (BER) below 3.8 × 10⁻³. The second sub-band transmission based on 32-QAM mapping can achieve a BER below 2.4 × 10⁻². The spectral efficiency (SE) of the first sub-band signal is up to 6.14 bit/s/Hz and the SE of the second sub-band signal is up to 4.39 bit/s/Hz.

中文翻译：

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使用基于RTZ DAC和次奈奎斯特采样ADC的具有成本效益的双频带传输方案来提高光学IMDD系统的数据速率

提出了一种基于零归零（RTZ）模式的数模转换器（DAC）和次奈奎斯特采样模数转换器（ADC）的经济高效的双频带传输方案。该方案可以增加数据速率，同时将光强度调制直接检测（IMDD）传输系统中DAC / ADC的所需采样率减半。基于此方案，我们通过实验证明了双频带离散傅立叶变换扩展（DFT-S）OFDM强度调制直接检测（IMDD）系统。尽管用于接收器的DAC和ADC的采样率仅为5-GSa / s，并且在发送器和接收器侧没有混频器和振荡器，但22 km标准单模光纤（SSMF）传输速率高达26.33 -Gb / s数据速率已成功实现。⁻³。基于32-QAM映射的第二子带传输可以实现BER低于2.4×10 ^-2。第一子带信号的频谱效率（SE）高达6.14 bit / s / Hz，第二子带信号的SE高达4.39 bit / s / Hz。