传统的可见光通信(VLC)调光方案利用冗余的补偿符号实现调光控制, 导致传输效率低。为了提高VLC系统传输效率, 提出一种基于整形极化码的调光控制方案, 通过预编码器改变码字中“1”出现的概率, 从而在无需添加冗余补偿符号的情况下实现调光控制功能。实验结果表明: 相比通过补偿符号实现调光控制的极化码方案, 整形极化码方案具备更高的传输效率和更好的纠错性能, 在25%和12.5%这2种典型的调光率场景中, 编码增益至少可以分别达到1.9 dB和3.3 dB。

针对强度调制直接检测-滤波器组多载波(IMDD-FBMC)系统中低比特位数数字模拟转换器(DAC)量化性能较差的问题，提出一种基于信号分布估计的非均匀量化方案。该方案采用基于FBMC信号分布的非线性规划方法获得量化误差最小时的量化阶距，进而提升基于低比特位数DAC的IMDD-FBMC系统性能。仿真结果表明:与均匀量化方式相比，该方案在3~5位量化比特位数的情况下可以使IMDD-FBMC系统的误码率(BER)性能提升15.9~60.7倍，且在保证系统性能的情况下，基于信号分布的量化方案可以减少1~2位量化比特位数，降低系统成本。

提出一种应用于强度调制直接检测光正交频分复用（IMDD-OFDM）传输系统的低开支、高准确度的信道估计算法.该算法充分考虑系统噪声特性，利用梳状导频插入结构，结合符号间平均与子载波间频域线性插值的思想，在低开支导频条件下实现较高的估计准确度.仿真和理论推导结果表明:与传统平均算法和直接线性插值算法相比，基于梳状导频先平均后线性插值的算法估计出来的信道特性更能接近实际信道的.实验结果表明：在误码率为3.8×10－3处，本文所提出的算法仅使用0.78%导频开支即可与使用20%导频开支的平均算法获得相同的接收灵敏度；同时，与传统估计算法相比，该算法与导频开支无关，能较好抗系统中的高斯噪声，获得与真实信道较为接近的估计性能.

针对发射端频率选择性IQ(同相/正交相)不平衡对CO-OFDM(相干光正交频分复用)系统传输性能的影响,提出一种基于DF(判决反馈)的IQ不平衡估计算法,并与传统的PA(导频插入)算法进行了对比.仿真研究和理论推演表明,所提算法可以有效地估计IQ不平衡和信道参数,提高系统的BER(误码率)性能.

拓扑学上的光网络由边（光传输）和节点（光交换）组成。从业务属性出发，基于连接和无连接方式，分析了光交换的时间结构，包括光分组和光突发的时间结构，以及不同动态性的光电路交换的时长及其度量标准，结合实验结果分析了最短光电路交换的时长极限。从多端口和大容量的要求出发，重点讨论了基于微电子机械系统(MEMS)开关、波长选择开关(WSS)和阵列波导光栅(AWG)的三种光交换结构。分析了光交换结构的扩展方法，并讨论了光交换的几个具有挑战性的问题，包括缓存和能耗问题。通过分析，希望从时间和空间两个维度更清晰地认识光交换的本质及其与电交换的异同。

In wavelength-division multiplexing (WDM) ethernet passive optical networks (EPONs), to realize the statistical multiplexing of upstream wavelength resources, some optical tunable components are introduced in the optical network units. However, the switch latency (SL) of these tunable components constrains the performance of WDM-EPON. In this letter, we extend the mathematical model of the WDM interleaved polling with adaptive cycle time (IPACT) scheme by additionally considering the SL conditions. We also investigate the effect of channel SL on network performance. The simulation results show that the performance of WDM-IPACT-SL deteriorates as the SL increases.

We propose and demonstrate a simple configuration of wavelength-tunable fiber laser made up of a tunable band-pass filter, a Sagnac loop reflector, and a Fabry-Perot laser diode. Based on the self-seeded operation, the proposed fiber laser can obtain a single-longitudinal-mode output in the wavelength tuning range of 1544.69–1563.39 nm with tuning step of 1.34 nm. The performances of output power (>-9 dBm), optical side-mode suppression ratio (> 65.5 dB), and power and wavelength stabilities are well exhibited.

We propose a novel wavelength-division multiplexed passive optical network (WDM-PON) to simultaneously transmit unicast data and multicast services with upstream data re-modulation in optical network units (ONUs). For each wavelength channel in the optical line terminal (OLT), the downstream unicast data are applied to one arm of a dual-parallel Mach-Zehnder modulator (DPMZM) to generate baseband unicast non-return-to-zero (NRZ) signal. A radio frequency (RF) control signal is applied to the other arm to present two un-modulated sidebands for multicast data modulation in a differential phase-shift keying (DPSK) format. The flexible and dynamic multicast services are realized by simply switching the RF control signal on or off. The proposed scheme is experimentally demonstrated with 1.25-Gb/s downstream unicast, multicast, and upstream data.

A hybrid wavelength division multiple access (WDMA)/optical code division multiplexing (OCDM) system is proposed, where the optical code is not the same as the address of every optical network unit (ONU); rather, the code is a virtual fiber of hybrid passive optical network (PON). To our knowledge, this is the first report analyzing a single encoder/decoder with a single corresponding optical code being exploited to encode/decode multiple wavelength signals simultaneously. This system enables OCDM to become transparent to ONU so that the existing wavelength division multiplexing (WDM) PON can be upgraded. Thus, redesigning the optical line terminal and ONU can be easily accomplished, and greatly decreasing the number of encoder/decoder becomes possible. In experiment, we only employ two encoder/decoder pairs to combine two WDM-PONs in one fiber. Simulation results confirm the feasibility of the proposed system.

文章基于M-Z(Mach-Zehnder)干涉原理, 提出了一种新型光纤振动传感器方案, 该传感器能判断振动事件发生的位置。仿真分析研究了该定位式传感器的信号处理技术, 通过增大信号的带宽、延长信号的持续时间、增大信噪比和改善定位算法, 实现了较好的定位性能, 验证了该定位式光纤振动传感器方案的可行性。