Zou Dongdong, Chen Yongchao, Li Zibin, Li Fan, Ding Li, Sun Yidan, Li Jianping, Sui Qi, Yi Xingwen, Li Zhaohui
Opt Express. 2019 Feb 18;27(4):5696-5702. doi: 10.1364/OE.27.005696.
In this paper, we experimentally compare the performance of two different narrowband interference suppression schemes in 120 Gb/s intensity modulation and direct detection (IM/DD) system with discrete multi-tone (DMT) signal transmission for intra-data center interconnect (Intra-DCI). Digital pre-equalization and DFT-spread techniques are applied for system bandwidth limitation induced signal distortion compensation and signal peak to average power ratio (PAPR) reduction, respectively. Null-subcarriers reservation (NSR) and adaptive notch filter (ANF) techniques are compared during the suppression of digital-to-analog convertor (DAC) clock leakage induced narrowband interference. 1.2 dB and 1.8 dB DMT receiver sensitivity improvements can be achieved at a bit-error rate of 3.8 × 10 in optical back-to-back (OBTB) transmission when optimized NSR and ANF schemes are applied for narrowband interference cancellation, respectively. After 2-km single mode fiber (SMF) transmission, the required received optical power (ROP) of DMT signal with optimized NSR and ANF for narrowband interference cancellation at BER of 3.8 × 10 are -6.5 dBm and -7.1 dBm, respectively. Obviously, ANF outperforms NSR scheme in narrowband interference cancellation for DMT system.
在本文中，我们通过实验比较了两种不同的窄带干扰抑制方案在120 Gb/s强度调制与直接检测（IM/DD）系统中的性能，该系统用于数据中心内部互连（Intra-DCI）的离散多音（DMT）信号传输。数字预均衡和离散傅里叶变换扩频技术分别用于补偿系统带宽限制引起的信号失真以及降低信号峰均功率比（PAPR）。在抑制数模转换器（DAC）时钟泄漏引起的窄带干扰过程中，对空子载波预留（NSR）和自适应陷波滤波器（ANF）技术进行了比较。在光背靠背（OBTB）传输中，当分别应用优化的NSR和ANF方案进行窄带干扰消除时，在误码率为3.8×10时，DMT接收机灵敏度可分别提高1.2 dB和1.8 dB。经过2公里单模光纤（SMF）传输后，在误码率为3.8×10时，采用优化的NSR和ANF进行窄带干扰消除的DMT信号所需接收光功率（ROP）分别为-6.5 dBm和-7.1 dBm。显然，在DMT系统的窄带干扰消除方面，ANF优于NSR方案。
