Photonic time-stretched analog-to-digital converter: Fundamental concepts and practical considerations
Photonic time-stretched analog-to-digital converter: Fundamental concepts and practical considerations
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DOI：
10.1109/jlt.2003.821731
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发表时间：
2003-12-01
影响因子：
4.7
通讯作者：
Jalali, B
中科院分区：
文献类型：
--
作者：
Han, Y;Jalali, B
超宽带模数（A/D）转换是通信、仪器仪表和雷达系统面临的最关键问题之一。本文提出了一个全面的分析最近提出的时间拉伸A/D转换器。通过在数字化之前降低信号带宽，该技术为电子转换器的性能提供了革命性的增强。本文首先从基础物理学的角度分析了时间-波长变换，以及时间膨胀对信噪比的影响。然后构造了时间拉伸过程的详细数学描述。阐明了线性和非线性色散对电信号保真度的影响。单边带时间拉伸系统的设计问题，因为它们涉及到宽带操作，检查。解释了光功率谱密度不均匀所引起的问题，并介绍了克服这些问题的两种方法。作为概念的证明，120 GSa/s的实时数字化的20 GHz的信号被证明。最后，讨论了连续时间时间拉伸系统的设计问题和性能特点。
Ultra-wide-band analog-to-digital (A/D) conversion is one of the most critical problems faced in communication, instrumentation, and radar systems. This paper presents a comprehensive analysis of the recently proposed time-stretched A/D converter. By reducing the signal bandwidth prior to digitization, this technique offers revolutionary enhancements in the performance of electronic converters. The paper starts with a fundamental-physics analysis of the time-wavelength transformation and the implication of time dilation on the signal-to-noise ratio. A detailed mathematical description of the time-stretch process is then constructed. It elucidates the influence of linear and nonlinear optical dispersion on the fidelity of the electrical signal. Design issues of a single-sideband time-stretch system, as they relate to broad-band operation, are examined. Problems arising from the nonuniform optical power spectral density are explained, and two methods for overcoming them are described. As proof of the concept, 120 GSa/s real-time digitization of a 20-GHz signal is demonstrated. Finally, design issues and performance features of a continuous-time time-stretch system are discussed.