Point-to-multi-point (PtMP) optical networks become the main solutions for network-edge applications such as passive optical networks and radio access networks. Entropy-loading digital subcarrier multiplexing (DSCM) is the core technology to achieve low latency and approach high capacity for flexible PtMP optical networks. However, the high peak-to-average power ratio of the entropy-loading DSCM signal limits the power budget and restricts the capacity, which can be reduced effectively by clipping operation. In this paper, we derive the theoretical capacity limitation of the flexible PtMP optical networks based on the entropy-loading DSCM signal. Meanwhile, an optimal clipping ratio for the clipping operation is acquired to approach the highest capacity limitation. Based on an accurate clipping-noise model under the optimal clipping ratio, we establish a three-dimensional look-up table for bit-error ratio, spectral efficiency, and link loss. Based on the three-dimensional look-up table, an optimization strategy is proposed to acquire optimal spectral efficiencies for achieving a higher capacity of the flexible PtMP optical networks.

翻译：点对多点（PtMP）光网络成为无源光网络和无线接入网等网络边缘应用的主要解决方案。熵加载数字子载波复用（DSCM）是实现灵活PtMP光网络低延迟并接近高容量的核心技术。然而，熵加载DSCM信号的高峰均功率比限制了功率预算并制约了容量，而削波操作可有效降低该比值。本文推导了基于熵加载DSCM信号的灵活PtMP光网络的理论容量限制，同时获得了削波操作的最优削波比以逼近最高容量限制。基于最优削波比下的精确削波噪声模型，我们建立了误码率、频谱效率和链路损耗的三维查找表。基于该三维查找表，提出了一种优化策略，通过获取最优频谱效率来实现灵活PtMP光网络更高容量。