Wang Bin, Cheng Yihao, Yu Weizhen, Hong Xu, Zhang Weifeng
Opt Express. 2023 Jul 3;31(14):23309-23324. doi: 10.1364/OE.494964.
Multi-channel microwave photonic (MWP) signal processing can simultaneously perform different task operations on multiple signals carried by multiple wavelengths, which holds great potential for ultrafast signal processing and characterization in a wavelength-division-multiplexed (WDM) network. As emerging telecommunication services create more data, an elastic optical network, which has a flexible and non-uniform spectrum channel spacing, is an alternative architecture to meet the ever-increasing data transfer need. Here, for the multi-channel ultra-fast signal processing in the elastic optical network, we propose and demonstrate an on-chip non-uniformly spaced multi-channel microwave photonic signal processor based on an ultrahigh-Q multimode micro-disk resonator (MDR). In the proposed signal processor, an MDR supporting multiple different order whispering-gallery modes (WGMs) with an ultrahigh Q-factor is specifically designed. Benefiting from the large and different free spectral ranges (FSRs) provided by the different order WGMs, a non-uniformly spaced multi-channel microwave photonic signal processor is realized, and various processing functions are experimentally demonstrated including bandpass filtering with a narrow passband of 103 MHz, a rejection ratio of 22.3 dB and a frequency tuning range from 1 to 30 GHz, multiple frequency measurement with a frequency measurement range from 1 to 30 GHz, a frequency resolution better than 200 MHz and a measurement accuracy of 91.3 MHz, and phase shifting with a phase tuning range from -170°∼160°, an operational bandwidth of 26 GHz from 6 GHz to 32 GHz and a small power variation of 0.43 dB. Thanks to the coexistence of different order WGMs supported by the MDR, non-uniformly spaced multi-channel signal processing is enabled with the key advantages including a broad operation bandwidth, an ultra-narrow frequency selectivity, and a large phase tuning range with a small power variation. The proposed signal processor is promising to be widely used in future elastic optical networks with flexible spectrum grids.
多通道微波光子（MWP）信号处理能够在多个波长所承载的多个信号上同时执行不同的任务操作，这在波分复用（WDM）网络中的超快信号处理和特性表征方面具有巨大潜力。随着新兴电信服务产生更多数据，具有灵活且非均匀频谱信道间距的弹性光网络是满足不断增长的数据传输需求的一种替代架构。在此，针对弹性光网络中的多通道超快信号处理，我们提出并演示了一种基于超高Q值多模微盘谐振器（MDR）的片上非均匀间距多通道微波光子信号处理器。在所提出的信号处理器中，专门设计了一种支持多种不同阶回音壁模式（WGMs）且具有超高Q因子的MDR。受益于不同阶WGMs提供的大且不同的自由光谱范围（FSRs），实现了非均匀间距多通道微波光子信号处理器，并通过实验演示了各种处理功能，包括具有103 MHz窄通带、22.3 dB抑制比以及1至30 GHz频率调谐范围的带通滤波，频率测量范围为1至30 GHz、频率分辨率优于200 MHz且测量精度为91.3 MHz的多频率测量，以及相移范围为 -170°至160°、6至32 GHz的26 GHz工作带宽且功率变化小至0.43 dB。得益于MDR支持的不同阶WGMs的共存，实现了非均匀间距多通道信号处理，其关键优势包括宽工作带宽、超窄频率选择性以及大相移范围且功率变化小。所提出的信号处理器有望在具有灵活频谱网格的未来弹性光网络中得到广泛应用。
