Coherent detection has the primary advantage of optical field recovery, which enables channel impairment compensation and advanced modulation formats for high-capacity transmission. On the other hand, direct detection (DD) is more cost-effective due to its local oscillator (LO)-free detection. To gain the field recovery advantage while preserving the LO-free detection for DD-based receivers, carrier assisted differential detection (CADD) has been proposed to retrieve the complex-valued double-sideband (DSB) signal. In this paper, to extend the concept of CADD, we propose a simplified CADD scheme with reduced hardware complexity and present signal-to-signal beating interference (SSBI) iterative mitigation algorithms with and without symbol decision. The required number of photodetectors and analog-digital converters (ADCs) for the simplified CADD receiver becomes the same as the coherent homodyne counterpart but without needing the expensive narrow-linewidth LOs. The performance of the proposed simplified CADD receiver is evaluated by 60-Gbaud 16-QAM DSB signals. Extensive performance comparisons are made between (i) the generalized CADD receivers with and without the simplified receiver structure, (ii) SSBI iterative mitigation algorithm with and without the symbol decision, and (iii) single carrier (SC) and OFDM-modulated DSB signals for the simplified CADD receiver.

中文翻译：

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具有通用和简化接收器结构的载波辅助差分检测


相干检测的主要优点是光场恢复，可以实现通道损伤补偿和高级调制格式，以实现高容量传输。另一方面，直接检测（DD）由于其无本地振荡器（LO）检测而更具成本效益。为了获得场恢复优势，同时保留基于 DD 的接收器的无 LO 检测，提出了载波辅助差分检测 (CADD) 来检索复值双边带 (DSB) 信号。在本文中，为了扩展 CADD 的概念，我们提出了一种简化的 CADD 方案，降低了硬件复杂性，并提出了带或不带符号判决的信号间跳动干扰 (SSBI) 迭代缓解算法。简化的 CADD 接收器所需的光电探测器和模数转换器 (ADC) 数量与相干零差接收器相同，但不需要昂贵的窄线宽 LO。所提出的简化 CADD 接收器的性能通过 60-Gbaud 16-QAM DSB 信号进行评估。在 (i) 具有和不具有简化接收器结构的通用 CADD 接收器、(ii) 具有和不具有符号判决的 SSBI 迭代缓解算法以及 (iii) 单载波 (SC) 和 OFDM 调制 DSB 信号之间进行了广泛的性能比较用于简化的 CADD 接收器。