Coded Modulation for 100G Coherent EPON
Coded Modulation for 100G Coherent EPON
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DOI：
10.1109/jlt.2019.2940889
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发表时间：
2020-02
影响因子：
4.7
通讯作者：
T. Gerard;Hubert Dzieciol;E. Sillekens;Y. Wakayama;A. Alvarado;R. Killey;P. Bayvel;D. Lavery
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文献类型：
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作者：
T. Gerard;Hubert Dzieciol;E. Sillekens;Y. Wakayama;A. Alvarado;R. Killey;P. Bayvel;D. Lavery
几何形状（GS）的8元，16元和32元调制格式的研究用于相干无源光网络。调制格式被设计为在与诸如低密度奇偶校验（LDPC）之类的二进制软判决前向纠错码（SD-FEC）配对时提高接收机灵敏度。在这里，我们考虑在草案50 G EPON标准中规定的LDPC码，并显示这种类型的代码如何可以在相干传输系统中特别有利。对于25 GBd的偏振加扰32进制GS调制格式，在FEC后误码率低于3.8 × 10 - 6时，接收机灵敏度为26.7 dBm，使用单极化相位分集相干接收机接收。这产生了100 Gbit/s的比特率，不包括编码和导频开销。这种调制格式在传输中表现同样良好，在80 km标准单模光纤后没有观察到色散损失。最后，使用基于单个平衡光电二极管的外差相干接收器以50 Gbit/s的降低的数据速率接收该调制格式。这种简化接收机配置的接收机灵敏度为28.5 dBm，功率预算为34.2 dB。
Geometrically shaped (GS) 8-, 16, and 32-ary modulation formats are investigated for use in coherent passive optical networks. The modulation formats are designed to improve receiver sensitivity when paired with a binary, soft-decision forward error correction code (SD-FEC), such as a low density parity check (LDPC). Herein we consider the LDPC code specified in the draft 50G EPON standard, and show how this type of code can be particularly advantageous in a coherent transmission system. A receiver sensitivity of $-$26.7 dBm is achieved at a post-FEC bit error rate below 3.8 $\times 10^{-6}$ for a polarization-scrambled 32-ary GS modulation format at 25 GBd, received using a single-polarization, phase-diverse coherent receiver. This yielded a bit rate of 100 Gbit/s, net of coding and pilot overhead. This modulation format was shown to perform equally well in transmission, with no observed dispersion penalty after 80 km standard single mode fiber. Finally, this modulation format was received, at a reduced data rate of 50 Gbit/s, using a heterodyne coherent receiver based on a single balanced photodiode. The receiver sensitivity for this simplified receiver configuration was $-$28.5 dBm, yielding a power budget of 34.2 dB.