Commercial coherent receivers utilize balanced photodetectors (PDs) with high single-port rejection ratio (SPRR) to mitigate the signal-signal beat interference (SSBI) due to the square-law detection process. As the symbol rates of coherent transponders are increased to 100 Gbaud and beyond, maintaining a high SPRR in a cost-effective manner becomes more and more challenging. One potential approach for solving this problem is to leverage the concept of single-ended coherent receiver (SER) where single-ended PDs are used instead of the balanced PDs. In this case, the resulting SSBI should be mitigated in the digital domain. In this paper, we show that SSBI can be effectively mitigated using various low-complexity techniques, such as the direct filed reconstruction (DFR), clipped iterative SSBI cancellation (CIC) and gradient decent (GD). In addition, we present a self-calibration technique for SERs which can be extended for characterizing the optical-to-electrical (O/E) response of a conventional balanced coherent receiver (BR). Using the developed techniques, we then experimentally demonstrate a 90 Gbaud probabilistically constellation shaped 64-QAM (PCS-64QAM) transmission using a SER, achieving a net data rate of 882 Gb/s over 100 km of standard single mode fiber (SSMF). The sensitivity penalty compared to the BR is below 0.5 dB. We expect that when the symbol rate is increased further, a SER can potentially outperform a BR, especially when applied to cost-sensitive commercial pluggable coherent transceivers
翻译:商业一致性接收器使用平衡的光检测器(PD),且单端拒绝率(SPRR)高,以缓解由于平方法律检测过程造成的信号信号信号节拍干扰(SSBI)。随着一致转发器的符号率提高到100Gbaud及以上,以成本效益高的方式保持高的SPR也越来越具有挑战性。解决这一问题的一个潜在办法是利用单端统一接收器(SER)的概念,即使用单端标准接收器而不是平衡的PD(SPR)。在这种情况下,由此产生的SSBI应在数字域内减少。在本文件中,我们表明SSBI可以使用各种低兼容度技术(SSBI)有效减缓,例如直接存档的重建(DFRR)、剪接的迭接式SPRR(CIC)和梯度等。此外,我们为SERS(S)提供了一种自我校准技术,在光向电压平衡接收器(O/EE)的特性上可以扩大一个常规平衡接收器(BRR)的响应。使用开发技术,然后我们实验性地展示了一种低于GAMA-R8的递模比例,在GAB标准上更低的递压压时,也就是一个比的BRBRBRB的递增率。我们可以进一步使用一种比的递增的递增的递增压压压压压。