Data centers, the engines of the global Internet, rely on powerful high-speed optical interconnects. In optical fiber communication, classic direct detection captures only the intensity of the optical field, while the coherent detection counterpart utilizes both phase and polarization diversities at the expense of requiring a narrow-linewidth and high-stability local oscillator (LO). Herein, we propose and demonstrate a four-dimensional Jones-space optical field recovery (4-D JSFR) scheme without an LO. The polarization-diverse full-field receiver structure captures information encoded in the intensity and phase of both polarizations, which can be subsequently extracted digitally. To our knowledge, our proposed receiver achieves the highest electrical spectral efficiency among existing direct detection systems and potentially provides similar electrical spectral efficiency as standard intradyne coherent detection systems. The fully recovered optical field extends the transmission distance beyond the limitations imposed by fiber chromatic dispersion. Moreover, the LO-free advantage makes 4-D JSFR suitable for photonic integration, offering a spectrally efficient and cost-effective solution for massively parallel data center interconnects. Our results may contribute to the ongoing developments in the theory of optical field recovery and the potential design considerations for future high-speed optical transceivers.

中文翻译：

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四维直接检测接收器可实现具有相位和偏振分集的琼斯空间场恢复

数据中心是全球互联网的引擎，依赖于强大的高速光纤互连。在光纤通信中，经典的直接检测仅捕获光场的强度，而相干检测对应物利用相位和偏振分集，但代价是需要窄线宽和高稳定性本地振荡器（LO）。在此，我们提出并演示了一种没有 LO 的四维琼斯空间光场恢复 (4-D JSFR) 方案。偏振分集全场接收器结构捕获以两种偏振的强度和相位编码的信息，随后可以数字方式提取这些信息。据我们所知，我们提出的接收器在现有直接检测系统中实现了最高的电频谱效率，并且有可能提供与标准内差相干检测系统类似的电频谱效率。完全恢复的光场扩展了传输距离，超越了光纤色散的限制。此外，无 LO 的优势使 4-D JSFR 适用于光子集成，为大规模并行数据中心互连提供光谱高效且经济高效的解决方案。我们的结果可能有助于光场恢复理论的持续发展以及未来高速光收发器的潜在设计考虑。