Misra Arijit, Kress Christian, Singh Karanveer, Meier Janosch, Schwabe Tobias, Preussler Stefan, Scheytt J Christoph, Schneider Thomas
Opt Express. 2022 Apr 11;30(8):13776-13789. doi: 10.1364/OE.454163.
We demonstrate for the first time, to the best of our knowledge, reconfigurable and real-time orthogonal time-domain detection of a high-bandwidth Nyquist signal with a low-bandwidth silicon photonics Mach-Zehnder modulator based receiver. As the Nyquist signal has a rectangular bandwidth, it can be multiplexed in the wavelength domain without any guardband as a part of a Nyquist-WDM superchannel. These superchannels can be additionally multiplexed in space and polarization. Thus, the presented demonstration can open a new possibility for the detection of multidimensional parallel data signals with silicon photonics. No external pulse source is needed for the receiver, and frequency-time coherence is used to sample the incoming Nyquist signal with orthogonal sinc-shaped Nyquist pulse sequences. All parameters are completely tunable in the electrical domain. The feasibility of the scheme is demonstrated through a proof-of-concept experiment over the entire C-band (1530 nm-1560 nm), employing a 24 Gbaud Nyquist QPSK signal due to experimental constraints on the transmitter side electronics. However, the silicon Mach-Zehnder modulator with a 3-dB bandwidth of only 16 GHz can process Nyquist signals of 90 GHz optical bandwidth, suggesting a possibility to detect symbol rates up to 90 GBd in an integrated Nyquist receiver.
据我们所知，我们首次展示了基于低带宽硅光子马赫-曾德尔调制器接收器对高带宽奈奎斯特信号进行可重构实时正交时域检测。由于奈奎斯特信号具有矩形带宽，它可以作为奈奎斯特波分复用（Nyquist-WDM）超通道的一部分在波长域中进行复用，无需任何保护带。这些超通道还可以在空间和偏振中进行复用。因此，所展示的演示为利用硅光子学检测多维并行数据信号开辟了新的可能性。该接收器无需外部脉冲源，并且利用频率-时间相干性通过正交的 sinc 形奈奎斯特脉冲序列对输入的奈奎斯特信号进行采样。所有参数在电域中均可完全调谐。由于发射机侧电子设备的实验限制，通过在整个 C 波段（1530 纳米 - 1560 纳米）进行的概念验证实验，采用 24 Gbaud 奈奎斯特 QPSK 信号，证明了该方案的可行性。然而，具有仅 16 GHz 3 dB 带宽的硅马赫-曾德尔调制器能够处理 90 GHz 光带宽的奈奎斯特信号，这表明在集成奈奎斯特接收器中有可能检测高达 90 GBd 的符号率。
