Redundancy-Free Key Distribution Using Multiple Phase Offset for Secure Data Center

This article proposes a redundancy-free multiple phase-offset based key distribution (MPO-KD) scheme for solving the physical-layer session key agreement in optical data center interconnections (DCIs). High-dimensional chaotic encryption is a promising technology expected to provide better security for massive-scale data transmission in DCIs. Considering the huge key space introduced by hyper-chaos, the proposed scheme converts digital keys into the phase of quadrature amplitude modulation (QAM) symbols by actively introducing controllable offsets. The solution of offset factor space is modeled as a multi-objective optimization problem for improving the key distribution performance. The Pareto optimal set is obtained using the non-dominated sorting moth-flame optimization (NS-MFO) algorithm. The two-channel 140 Gb/s 16-QAM, 176 Gb/s 32-QAM and 210 Gb/s 64-QAM orthogonal frequency division multiplexing (OFDM) signal transmissions are successfully demonstrated. The results indicate that this scheme achieves error-free key distribution without degrading system performance, which supports an expandable large key space and has good compatibility with various encryption algorithms.

I. Introduction

In Recent years, as the progress of digital transformation and upgrade in various internet industries has accelerated, data centers (DCs) have become a core infrastructure to support the explosive demand for large-capacity data storage, computation, transmission, and applications [1]. To meet the fast-growing traffic, low-latency and low-cost requirements, optical transmission technologies have been extensively applied in point-to-point inter-data center interconnections (DCIs) [2], [3]. The coherent detection transceiver enables better performance at the cost of complex hardware components. In contrast, intensity modulation and direct detection (IMDD) based optical link has been a more attractive solution for short-reach DCIs due to various benefits, such as lower implementation cost and power consumption [4]. Moreover, to increase the data rate of a single wavelength channel while relaxing the bandwidth limitation for optical devices with the next generation standardization of 800 GbE or even 1.6 TbE [5], the high-order quadrature amplitude modulation (QAM) format has been widely studied and demonstrated to realize over 100Gb/s per dimension in optical transmission [6], [7], [8]. Direct detection optical orthogonal frequency division multiplexing (OFDM) technology is also used to improve the spectrum efficiency and withstand the inter-symbol interference (ISI) caused by chromatic dispersion and nonlinearities [9], [10].