A scheme of flexible colorless remote note with reflective semiconductor optical amplifier (RSOA) assisted Michelson interferometer is proposed. This is capable of generating an optical carrier suppressed signal at a specific radio frequency to suppress the penalty brought about by Rayleigh backscattering and reflection in a full-duplex single fiber transmission network. Simulations are conducted, and the validation of the proposal is discussed by observing the penalty eye opening factor. The results are useful for designing cost-effective multi-wavelength passive optical network (PON) or radio-over-fiber (RoF) systems.

文章主要对一种基于微波接入全球互通(WiMAX)的宽带无线接入网的射频光纤传输系统的方案进行了研究。该方案主要描述了系统的中心站与基站间的下行链路的结构。对其功率预算和载波带宽选择问题进行了理论推导和分析。其分析结果对该系统在功率以及载波带宽选择方面具有一定的指导意义。

The present paper proposes a novel design for achieving single-polarization single-mode (SPSM) operation at 1550 nm in photonic crystal fiber (PCF), using a rectangular-lattice PCF with two lines of three central air holes enlarged. The proposed PCF composed entirely of silica material is modeled by a full-vector finite element method with anisotropic perfectly matched layers. Simulations show that single-polarization operation within broad wavelength range can be easily realized with the proposed structure. The wide-band SPSM operation features, the low confinement losses, and the small effective mode area are the main advantages of the proposed PCF structure. A SPSM-PCF with confinement loss less than 0.1 dB/km within wavelength range from 1370 to 1610 nm and effective mode area about 4.7 micron2 at 1550 nm is numerically demonstrated.

应用全矢量有限元方法，分析了椭圆形高折射率芯Bragg光纤的偏振和色散特性，详细讨论了光纤结构参量对模式双折射的影响，结果发现：椭圆形高折射率芯Bragg光纤的模式双折射在10^－3量级，比传统保偏光纤高出一个量级，且随波长的增加而单调递增；模式双折射随包层低折射率材料填充比的增加而减小，但与包层周期的变化几乎无关．此外，提高椭圆率或材料间的折射率比可显著增强模式双折射．研究结果有助于设计高性能的一维微结构保偏光纤．

提出了光突发交换网络中的最长队列优先调度(LQF－SA)机制，将边缘节点的突发组装和突发调度两种技术紧密结合在一起．在现实网络中，业务通常是非均匀分布的，即在某些源宿对之间存在更大的业务流量．仿真结果表明，LQF－SA机制可以很好地完成非均匀分布业务流的组装．即使在均匀分布业务流输入下，LQF－SA机制在突发大小分布、组装效率和突发丢失率等方面也优于已提出的轮询调度组装(RR－SA)机制．

提出一种新型的光分组信头净荷分离方案．利用一个非对称半导体光放大器马赫－曾德尔干涉仪提取出信头脉冲，然后再利用对称的SOA－MZIs构建异或门，完成信头脉冲和光分组脉冲在差分调制下的逻辑运算，提取出净荷脉冲．在50 Gb／s速率下，数值仿真表明提取出的信头和净荷信号的开关比均超过16 dB．此外通过更改参数设置．该方案还可以应用到不同速率，不同信头长度的信头净荷分离中．

通过对光开关和节点流量进行建模，利用新颖的等效串扰系数法，研究了基于XGM效应的SOA开关矩阵在OPS网络中的串扰问题．分析了SOA的各种参量以及节点流量特性对开关隔离度、节点中由串扰造成的误码率以及节点级联能力的影响．提出了优化SOA交换矩阵的具体措施，包括提高SOA的载流子寿命、控制脉冲能量和节点中流量的单播特性，以及降低SOA的饱和能量和有源区长度等．

利用半导体光放大器增益饱和数学模型，第一次分析了基于单个半导体放大器进行光标签提取的节点性能．通过对半导体光放大器的参量分析和优化，仿真显示，对于标签速率2．5Gb／s、净荷速率40Gb／s的光分组包，提取的标签消光比可达到13dB．

A novel scheme for all-optical inverted wavelength conversion with 40-Gb/s pseudorandom bit sequences (PRBSs) based on a modified terahertz optical asymmetric demultiplexer (TOAD) is proposed. The performance of the proposed wavelength converter is analyzed in term of extinction ratio (ER) through numerical simulations. For a typical ER of 10 dB, some key characteristic parameters of the semiconductor optical amplifier (SOA) are designed. With the properly designed parameters, a high quality eye diagram is achievable, indicating that the amplitude fluctuation of the output signal is effectively reduced.

Nonlinear-optical-loop-mirror-based wavelength conversion is studied in details. A set of two-phase-shifted Bragg gratings are introduced into the coverter, serving as a narrow band-pass filter to remove new frequencies generated by walk-off and to compensate the dispersion. Numerical simulations are performed to validate our method. The results show that the converted pulses after the filter are reshaped and, sometimes, even compressed.