Ultrawideband Sampling

无线通信计量必须正确地表示数字和模拟信号域的复杂相互作用。太赫兹频率的高带宽允许极端射频（RF）带宽，因此也有非常大的基带带宽。在基带，宽带模拟信号通过宽带模数转换器（ADC）进行数字化处理。在ADC中，首先对信号进行采样，然后将模拟采样流转换为数字数据字流。通常是采样的精度决定了ADC的精度。模拟输入信号的高带宽要求极快的采样器，采样器带宽不足将导致信号退化。除了带宽，宽带采样器的另一个主要性能瓶颈是孔径抖动rsp。电子钟的时钟抖动。作为一种替代方案，基于锁模激光器（MLL）脉冲序列的光学时钟已被证明比电子钟实现更小的抖动。这导致了使用超低抖动光时钟的光子采样器和adc的发展。到目前为止，大多数光子采样技术都使用离散光学器件和大型复杂的实验室装置。近年来，磷化铟技术和硅光子学等光子集成技术取得了重大进展，使得光子采样电路（除MLL外）可以像电子采样器一样集成。这将允许机械稳定，小型化和低成本的光子采样设备。在METERACOM的项目中，来自pi公司Scheytt和Schneider的团队将研究带宽高达40ghz的超宽带电子和光子采样技术的不同版本，以满足太赫兹无线通信的要求，以及它们的集成适用性。B3的三个目标是：1)从理论上和实验上研究太赫兹波形采样的不同光子采样技术；2)首次在硅光子芯片上实现一种新的超宽带光子采样技术（频率-时间相干采样）；3)对电子和光子采样技术进行建模和比较，找到最适合集成的超宽带采样技术。调查将通过数学分析、数值模拟和模拟以及不同取样装置的测量来进行。

The metrology of wireless communication has to properly represent the complex interaction of the digital and analog signal domains. The high bandwidth at THz frequencies allows for extreme radio frequency (RF) bandwidth and hence also very large baseband bandwidth. In the baseband the broadband analog signals are digitized by broadband analog-to-digital-converters (ADC). In an ADC the signal is first sampled and then the stream of analog samples is converted to a stream of digital data words. Typically it is the precision of the sampling which determines the precision of the ADC. The high bandwidths of the analog input signals require extreme fast samplers and insufficient sampler bandwidth will be a cause for signal degradation. Besides bandwidth, another major performance bottleneck of broadband samplers is aperture jitter rsp. clock jitter of the electronic clock. As an alternative, optical clocks based on pulse trains from mode-locked lasers (MLL) have demonstrated to achieve much smaller jitter than electronic clocks. This has led to the development of photonic samplers and ADCs using ultra-low-jitter optical clocks. So far most of the photonic sampling techniques use discrete optical devices and large, complex laboratory setups. Recently photonics integration technology such as indium phosphide technology and silicon photonics have made significant progress and allow to integrate photonic sampling circuits (except the MLL) in a similar way as electronic samplers. This will allow for mechanically stable, miniaturized, and cost-efficient photonic sampling devices. In the projct of METERACOM the groups from PIs Scheytt and Schneider will investigate different variants of ultra-broadband electronic and photonic sampling techniques with bandwidth up to 40 GHz as required for THz wireless communication and their suitability for integration. The three goals of B3 are: 1) to investigate different photonic sampling techniques for the sampling of THz waveforms both theoretically and experimentally, 2) to implement a novel ultra-broadband photonic sampling technique (frequency-time-coherent sampling) for the first time in a silicon photonic chip and 3) to model and compare electronic and photonic sampling techniques and find the ultra-broadband sampling technique which is best suited for integration. Investigations will be carried out by means of mathematical analysis, numerical modeling and simulation, as well as measurements of different sampling devices.