Single-photodiode-per-polarization coherent receivers (SCRs) can preserve all of the merits of the conventional digital coherent receivers (DCRs) such as supporting chromatic dispersion (CD) compensation and polarization multiplexing, whilst have much lower optical complexity. But the overall algorithm complexity of the SCRs is relatively higher because an extra dedicated field reconstruction algorithm (FRA) is required in addition to the standard algorithms used in DCRs. The heavy computation burden introduced by the FRA poses a major obstacle to reduce the DSP chip size and power consumption. In this paper we propose a method to reduce the overall algorithm complexity of the SCR by utilizing several techniques, including utilizing a strong local oscillator (LO) to mitigate the signal-signal beat interference (SSBI), a pseudo-single-side-band signal to recovery the signal field and a new FRA to reuse the operations in the CD compensation algorithm to realize field reconstruction. Other than reducing the overall algorithm complexity, the new method also make the SCR more robust to laser frequency offset compared with the existing heterodyne detection based FRA. Numerical simulations and experiments are presented to demonstrate the merits of new method with respect to the existing ones.

中文翻译：

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一种降低单光电二极管每极化相干接收机算法复杂度的方法

每偏振单光电二极管相干接收器 (SCR) 可以保留传统数字相干接收器 (DCR) 的所有优点，例如支持色散 (CD) 补偿和偏振复用，同时具有低得多的光学复杂性。但 SCR 的整体算法复杂度相对较高，因为除 DCR 中使用的标准算法外，还需要额外的专用场重建算法 (FRA)。FRA 引入的繁重计算负担对降低 DSP 芯片尺寸和功耗构成了主要障碍。在本文中，我们提出了一种通过利用多种技术来降低 SCR 整体算法复杂度的方法，包括利用强本地振荡器 (LO) 来减轻信号-信号差拍干扰 (SSBI)，一个伪单边带信号来恢复信号场和一个新的FRA来重用CD补偿算法中的操作来实现场重建。除了降低整体算法的复杂度外，与现有的基于外差检测的 FRA 相比，新方法还使 SCR 对激光频率偏移具有更强的鲁棒性。数值模拟和实验被提出来证明新方法相对于现有方法的优点。