Comparison of 128-SP-QAM with PM-16-QAM.
Comparison of 128-SP-QAM with PM-16-QAM.
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DOI：
10.1364/oe.20.008356
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发表时间：
2012-04
期刊：
影响因子：
3.8
通讯作者：
M. Sjödin;P. Johannisson;Jianqiang Li;E. Agrell;P. Andrekson;M. Karlsson
中科院分区：
文献类型：
--
作者：
M. Sjödin;P. Johannisson;Jianqiang Li;E. Agrell;P. Andrekson;M. Karlsson
本文研究了一种有趣的光纤通信调制格式，即集分128偏振复用16-QAM (128- sp - qam)，它由偏振复用16-QAM （PM-16-QAM）符号字母表中的偶宇称符号组成。我们使用数值模拟比较了128-SP-QAM和PM-16-QAM在112 Gbit/s和224 Gbit/s的比特率和相同的符号速率（14和28 Gbaud）下的长途传输场景。传输链路由标准单模光纤组成，放大器间距分别为60,80或100km，并研究了单通道和WDM传输（25 ghz和50 ghz间隔）。结果表明，在相同的数据速率下，128-SP-QAM在误码率为10⁻³的情况下，与PM-16-QAM相比，传输距离增加了40%以上。此外，我们发现在单通道传输中，与使用224 Gbit/s的数据速率相比，使用112 Gbit/s的数据速率在传输距离方面具有预期的优势。然而，当比较具有相同聚合数据速率的两种不同WDM系统时，由于在50 GHz间隔的系统中WDM信道之间的非线性串扰影响较小，因此覆盖范围相似。我们还讨论了128-SP-QAM的译码和相位估计，并实现了差分编码，避免了相位估计中由于周期跳引起的突发错误。包括激光相位噪声的模拟表明，两种格式的相位噪声容忍是相似的，对于激光线宽与符号率比为10⁻⁴的情况，与零相位噪声的情况相比，有0.5 dB的OSNR损失。
In this paper we investigate an interesting modulation format for fiber optic communications, set-partitioning 128 polarization-multiplexed 16-QAM (128-SP-QAM), which consists of the symbols with even parity from the symbol alphabet of polarization-multiplexed 16-QAM (PM-16-QAM). We compare 128-SP-QAM and PM-16-QAM using numerical simulations in long-haul transmission scenarios at bit rates of 112 Gbit/s and 224 Gbit/s, and at the same symbol rates (14 and 28 Gbaud). The transmission link is made up of standard single-mode fiber with 60, 80 or 100 km amplifier spacing and both single channel and WDM transmission (25- and 50 GHz-spaced) is investigated. The results show that 128-SP-QAM achieves more than 40% increase in transmission reach compared to PM-16-QAM at the same data rate for all cases studied for a bit error rate of 10⁻³. In addition, we find that in single channel transmission there is, as expected, an advantage in terms of transmission distance when using a data rate of 112 Gbit/s as compared to 224 Gbit/s. However, when comparing the two different WDM systems with the same aggregate data rates, the reach is similar due to the smaller impact of nonlinear crosstalk between the WDM channels in the systems with 50 GHz spacing. We also discuss decoding and phase estimation of 128-SP-QAM and implement differential coding, which avoids error bursts due to cycle slips in the phase estimation. Simulations including laser phase noise show that the phase noise tolerance is similar for the two formats, with 0.5 dB OSNR penalty compared to the case with zero phase noise for a laser linewidth to symbol rate ratio of 10⁻⁴.