Multi-level signaling in the Stokes space and its application to large-capacity optical communications.
Multi-level signaling in the Stokes space and its application to large-capacity optical communications.
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DOI：
10.1364/oe.22.007374
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发表时间：
2014-04
期刊：
影响因子：
3.8
通讯作者：
K. Kikuchi;S. Kawakami
中科院分区：
文献类型：
--
作者：
K. Kikuchi;S. Kawakami
光信号的Stokes矢量不依赖于其绝对相位，因此，可以用Stokes矢量作为调制参数来构造相位不敏感的光通信系统。在这样的系统中，可以有效地在三维斯托克斯空间中设计多级光信号，并通过直接检测或相干检测解调，其中采用低复杂度的数字信号处理（DSP）。虽然该系统存在自适应均衡器难以在数字域实现的缺点，但它仍然是大容量（≥ 100 Gbit/s）和中短距离（≤ 100 km）传输的一个有吸引力的解决方案。在本文中，我们讨论了接收机配置的多电平信号在斯托克斯空间和有效的DSP算法解调这样的信号。仿真结果表明，在Stokes空间中的2，4，8，16和32进制信号具有良好的误比特率（BER）特性。特别地，即使使用直接检测，在25 Gsymbol/s的中等符号速率下的16进制信号也可以达到100 Gbit/s的比特率。
The Stokes vector of an optical signal does not depend on its absolute phase; therefore, we can construct the phase-insensitive optical communication system, using the Stokes vector as a modulation parameter. In such a system, multi-level optical signals can effectively be designed in the three-dimensional Stokes space and demodulated either by direct detection or by coherent detection, where low-complexity digital-signal processing (DSP) is employed. Although this system has the disadvantage that adaptive equalizers can hardly be implemented in the digital domain, it is still an attractive solution to large-capacity (≥ 100 Gbit/s) and medium-or short-reach (≤ 100 km) transmission. In this paper, we discuss the receiver configuration for the multi-level signal in the Stokes space and the efficient DSP algorithm for demodulating such a signal. Simulation results demonstrate that 2-, 4-, 8-, 16-, and 32-ary signals in the Stokes space have good bit-error rate (BER) characteristics. Especially, the 16-ary signal at the moderate symbol rate of 25 Gsymbol/s can reach the bit rate of 100 Gbit/s even by using direct detection.