ADC/DAC resolution tolerance improvement by implementing probabilistic shaping distributions in PAM and QAM modulation schemes

In this paper, we simulated the ADC/DAC resolution tolerance improvement by implementing probabilistic shaping (PS) distributions in PAM and QAM modulation schemes for 400G and 800G transmissions. We compared PS- and uniformdistributed PM-16QAM, PM-32QAM, and PM-64QAM performance in 800G coherent transmission in FR links. The PS distribution scheme is based on Maxwell-Boltzmann distribution, and 0.1378 FEC overhead is chosen. We demonstrate that for any of these modulation schemes the post-BER (post-FEC bit-error rate) performance is more sensitive to ADC resolution. Moreover, the application of PS distribution can offer us 0.5-dB improvement in received optical power (ROP) for LDPC-coded PM-16QAM and 0.7-dB improvement for PM-32QAM, while PM-64QAM can get 0.6-dB improvement in ROP. For PAM transmission, we simulated a 4-channel CWDM 400G transmission system with wavelengths 1271 nm, 1291 nm, 1311 nm, and 1331 nm for 4-PAM modulation scheme. The PS distribution scheme we used in PAM is exponential distribution, and the FEC overhead is also 0.1378. We demonstrated that the pre-SER (pre-FEC symbol-error rate) performance is also more sensitive to the ADC resolution compared to DAC resolution. Therefore, the PS LPDCcoded modulation represents a great candidate to improve the system performance and reduce the cost. © 2021 SPIE.Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu