LIU Bo, WANG Chen, TAN Yu-xuan, ANG Kai-hui, DING Jun-jie, ZHU Bo-wen, TIAN Feng, SHEN Lei, ZHANG Lei, WANG Rui-chun, YAN Chang-kun, CHEN Wei-zhang, YE Bing, REN Jian-xin, LI Fan, DENG Lei, LI Jian-ping, QIN Yu-wen, LI Chao-hui, XIN Xiang-jun, YU Jian-jun
Online available: 2024-03-20
The mode division multiplexing (MDM) system based on the few mode fiber (FMF) can realize the parallel transmission of different independent channels by using the orthogonal modes in a single fiber core, which can effectively improve the system capacity and solve the “capacity crunch” of the single mode fiber (SMF) system. In this paper, we realize the transmission of the 32 Gbaud four-mode dual-polarization 16-ary quadrature amplitude modulation (16QAM) signals in 80 wavelength channels over 1000 km six-mode graded-index fiber by using jointly the MDM, wavelength division multiplexing (WDM) and polarization division multiplexing (PDM) techniques. In addition, we use the hybrid time-frequency domain data-assisted 8×8 multiple-input multiple-output (MIMO) least mean square (LMS) equalization at the receiver to compensate for the linear damages such as the mode coupling (MC) and differential mode group delay (DMGD) caused by the fiber transmission. Compared with the commonly used time-domain or frequency-domain MIMO-LMS equalization, the joint use of time and frequency domain can realize 57.1% improvement in convergence speed and 25.1% reduction in convergence error. After 1 000 km delivery of FMF, the bit error ratio (BER) of each mode and polarization state of all the 80 channels is lower than the 20% soft-decision forward error correction (SD-FEC) threshold of 2.4×10-2, and the net transmission rate is up to 68.2 Tbit/s.