In this paper, we propose and experimentally demonstrate a joint shaping technique to improve the performance of a lowresolution transmission system for the first time, to the best of our knowledge. The joint shaping technique combines probabilistic shaping (PS) and error feedback noise shaping (EFNS). In the 40-Gbaud intensity-modulation direct-detection (IM/DD) experimental transmission system, a bit-error-rate (BER) of 3.8 × 10 −3 can be achieved easily with the joint shaping at the physical number of bits (PNOB) of 3. In the 30-Gbaud dual polarization (DP) coherent experimental transmission system, a BER below 1 × 10 −3 is easily obtained with a 3-bit quantizer by using joint shaping. The optimization of the shaping degree is also analyzed.

We demonstrate the capability of the multimode fiber and photonic time-stretch based compressive sampling scheme to detect chirp radio frequency signals, with the advantages of fast speed, high accuracy, less complexity and low cost.

We propose a joint pre-compensation method based on digital resolution enhancer (DRE) and Tomlinson-Harashima precoding (THP) for low-resolution data center optical interconnect. DRE is utilized to reduce the quantization noise of the digital-to-analog converter (DAC), while THP is utilized to fall off the frequency fading caused by the system bandwidth limitation and chromatic dispersion. By combining THP and DRE, we can achieve a 112-Gb/s PAM4 system over a 40-km standard single-mode fiber with a physical number of bits (PNOB) = 4 DAC on the transmitter side Moreover, using THP in bandwidth-constrained systems can increase the transmission capacity by 26.15%.