【作者】 王静；

【导师】 邱昆；

【作者基本信息】 电子科技大学 ， 光学工程， 2016， 硕士

【摘要】 波分复用无源光网络(WDM-PON)由于其带宽大、灵活性高、成本低、效率高等优点被认为是最具前景的下一代光纤接入网技术之一。然而,随着网络用户数量和网络容量的爆炸式增长,光纤接入网的安全性越来越重要而且限制了通信网的进一步发展。到目前为止的大多数保密增强方案只考虑了介质访问控制层(MAC)或更高层,由于光纤链路易受到各种攻击,因此急需寻求一种保护光纤接入网物理层信息免受攻击的方法。将信息调制到由半导体激光器产生的宽带混沌信号中进行传输,广泛用来实现双向或单向的混沌同步通信,可以提高物理层的安全性。本文主要研究内容如下：研究了一种基于混沌同步的物理层保密增强的PON系统并对该系统进行了数值验证,在上行/下行传输中采用了外腔半导体激光器(ECSL)产生的混沌载波作为传输载波,混沌调制技术用于加密下行信息,上行信息的加密采用的是复合副载波调制技术。仿真结果表明PON系统可以实现信息双向同时传输,同时该系统的保密安全性也可以维持在很高的水平。在此基础上提出了改进的基于混沌同步的保密增强WDM-PON系统。数值仿真结果表明在波长间隔合适的情况下,OLT和ONUs之间相对应的半导体激光器可以达到高品质的混沌同步,最终系统实现了多信道上行/下行双向同时高速率的混沌通信,而且上行/下行信息的保密性也得到了进一步提升。创新性地提出了将基于混沌同步的保密增强WDM-PON和副载波调制技术(SCM)结合在一起,实现高速混沌物理层保密增强的WDM-SCM-PON的方案。在基于混沌同步的对称结构的WDM-SCM-PON系统中,讨论了在两个信道以及每个信道中有两个ONU的情况下该系统的通信性能和安全保密性。仿真结果表明：当波长间隔足够大时,每个信道中OLT和ONU之间传输的混沌载波可以达到很好的同步品质。同时,当副载波之间的频率间隔设置的比较合适时,每个信道中可以允许多个OLT和ONU之间的信息通过复合副载波调制技术进行传输。在此基础上实现了在WDM-SCM-PON系统中信息高速的双向同时传输,信息传输的速率达到上行/下行24 Gbit/s(每个信道为12 Gbit/s);同时当传输的信息速率小于6 Gbit/s时,上行/下行恢复信息的BER的值保持在10-6之下。更多还原

【Abstract】 Wavelength division multiplexed passive optical network (WDM-PON) has been considered as one of the most suitable candidates for the next generation broadband optical access network, for its attractive merits, such as broadband capability, economical cost, and low energy consumption, et al.. Nevertheless, with the sharp increasing of the communication network consumer number and the rapid development of network capacity, the security of optical access network has turned to be one key issue that would limit the development of communication networks. Up to present, most of the security solutions are focused on the data encryption at the media access control (MAC) layer or the higher layers. Under such a scenario, since the fiber link is vulnerable to kinds of attacks, it is valuable to enhance the security of physical layer of optical access network to guard the privacy of customers. In the last decade, the all-optical chaotic communication has been extensively studied, since that the broadband optical chaotic signal can well hide the message that is modulated into it, which can improve the security of the physical layer. The main research works are listed as follows:A physical-enhanced secure passive optical network (PON) based on chaos synchronization is introduced and numerically demonstrated. In this scheme, the chaotic output of an external-cavity semiconductor laser is used as the transmission carrier in both downstream and upstream directions, the chaos modulation technology is used to encrypt the downstream data, and the multiplexed subcarrier-modulation technology is adopted for the upstream transmission. Simulation results demonstrate that both the downstream data and the upstream data encrypted into the chaotic carriers can be successfully decrypted while the security can be maintained at a high level. Based on this, a physical security-enhanced wavelength division multiplexed passive optical network (WDM-PON) based on chaos synchronization between twin laser pairs is introduced. We numerically demonstrate that with sufficient wavelength spacing, a high quality chaos synchronization between the chaotic carriers with identical wavelength can be maintained, which enables the proposed WDM-PON to afford multichannel chaotic communications at high bit rates in both the downstream and upstream directions. The security of the physical layer can be greatly enhanced.A novel secure passive optical network (PON) configuration jointly based on the chaos synchronization of wavelength division multiplexed chaotic signals and the subcarrier modulation multiplexing is introduced. For the sake of simplicity, we take the case with two wavelengths and two subcarriers for instance, to demonstrate the concept of the proposed WDM-SCM-PON. The numerical results demonstrate that with proper selection of the wavelength spacing, high quality chaos synchronization can be achieved on each wavelength, and each wavelength can afford several OLT-ONU transmissions by properly allocating the frequency spacing of subcarriers. Based on this, a symmetric 24 Gbit/s (12 Gbit/s on each wavelength) chaotic WDM-SCM-PON is achieved. The BER for each OLT-ONU transmission is smaller than 10-6, as long as the bit rate is lower than 6 Gbit/s.更多还原