时分复用倍乘光脉冲重复率的新型光纤耦合器环状连接法分析

提出并详细分析了一种基于时分复用技术倍乘光脉冲重复率的方法：在２×２光纤耦合器的一个输入口与一个输出口间，接入时延为脉冲列半周期奇数倍的一段光纤使之形成环状连接循环耦合，而在另一输出口获得光脉冲。详细分析了该系统中光纤耦合器耦合比、插入损耗、时延光纤长度的要求，偏差的影响及其调节法，给出了理论公式、结果的计算机模拟与实验介绍；与经典的马赫陈德尔干涉仪接法及近年提出的Ｓａｇｎａｃ环接法进行了比较。该方法特别适用于对窄脉冲列进行串接复用实现重复率的多次倍乘，从而得到数千兆赫至上百千兆赫的高重复率光脉冲     

1×7圆柱形混合棒塑料光纤耦合器

提出一种新型的使用圆柱形混合棒的 1× 7塑料光纤耦合器。该耦合器直接使用粗塑料光纤制作混合棒 ,与传统的 1× 7圆锥形混合棒塑料光纤耦合器相比省略了成本高的混合棒拉锥过程 ,因而成本较低。对混合棒失配面外接U形光纤光吸收器的 1× 7圆柱形混合棒塑料光纤耦合器进行了理论分析和实验研究 ,实验测量该耦合器的通道串音小于 - 40dB ,其耦合效率接近于 1× 7圆锥形混合棒塑料光纤耦合器。实验结果表明该耦合器是一种高性能价格比的塑料光纤耦合器     

一种新型结构的单模光纤1×4分束器

以线性耦合波方程为基础，分析了具有平面型结构的五光纤耦合系统的功率耦合特性，提出了研制新型结构的单模光纤１×４分束器的方法，并经实验验证。所研制的１×４分束器的性能和外形尺寸与常规的２×２单模光纤耦合器相比，都较为接近。     

高性能三端口全光纤开关

提出采用２×２和３×３单模光纤耦合器组合成的马赫－陈德尔干涉仪来制作全光纤开关。解决了在连续熔融拉伸两个耦合器组成马赫－陈德尔干涉仪的过程中，由于干涉的作用而无法监视光功率来控制第二个耦合器的分束比的问题。并且由于是连续熔融拉伸，保证了两条单模光纤干涉臂长度的一致，从而提高了单模光纤马赫－陈德尔干涉仪的性能，使得用其做成的三端口压电陶瓷电控全光纤开关具有宽频带的特性，其最小交调达到３０ｄＢ，附加损耗为０．２３ｄＢ。     

40 Gbit/s非等幅编码光时分复用传输系统

4× 10Gb s非等幅编光时分复用 (OTDM)传输系统采用增益开关分布反馈式激光器 (GS DFB)产生超短光脉冲 ,通过色散补偿光纤 (DCF)和梳状色散光纤链 (CDPF)实现了脉冲的线性和非线性压缩 ;利用啁啾光纤光栅实现色散补偿 ;在接收端 ,利用电吸收调制器 (EAM)实现了光时分复用信号的解复用 ;同时采用非等幅编码方案提取帧时钟。整个系统经过 12 2km的G .6 5 2光纤传输之后 ,误码率小于 10 - 9。     

双芯光子晶体光纤宽带定向耦合器研究

利用半矢量有限差分法设计了具有低折射率双芯的光子晶体光纤宽带定向耦合器,并数值计算了双芯光子晶体光纤的结构参量对耦合性能的影响.数值结果表明,通过优化选取光子晶体光纤包层结构参量和纤芯掺杂浓度,双芯光子晶体光纤耦合器可以实现宽带耦合.在1.22~1.65 μm 波长范围内其耦合长度稳定在26637 nm±235 nm范围内,耦合器设计成耦合比为50%和10%,分别实现了耦合比为（50±0.702）%和（10±0.664）%的良好特性.     

高峰值功率脉冲激光与石英光纤耦合的空气击穿问题

 研究了15 MW峰值功率脉冲激光与600 μm芯径石英光纤耦合中存在的空气击穿现象。对聚焦区域的空气击穿现象进行了理论和实验研究,测得空气击穿阈值为0.79×10⁹ W/cm²。测得固体介质的激光损伤阈值为2.12×10⁹ W/cm²,与理论计算结果相符。提出了七合一光纤耦合器用于解决空气击穿的办法,实验测得7根光纤并束的耦合效率为67.21%。结果表明光纤耦合器可有效解决15 MW峰值功率脉冲激光与600 μm芯径石英光纤的耦合。     

多束高重复频率全光纤激光脉冲时间波形实时精密测量技术

提出了一种基于时分复用的多束高重复频率全光纤激光脉冲时间波形实时精密测量技术,针对分类成组的多束高重复频率全光纤激光系统不同测量功能需求,分别设计了1×8时分复用器、不同延时量的1×2时分复用器,实现了48路、144个1kHz光纤激光整形脉冲时间波形宽度、上升沿、面积等关键参数的精密测量,同时实现了多束高重复频率全光纤脉冲激光系统运行状态的实时监测。     

单模光纤耦合器带宽特性分析

本文由求解耦合系数随纵向距离变化的耦合波方程着手,提出了变间距单模光纤定向耦合器,讨论了这种耦合器的耦合特性。通过对耦合器各种损耗的分析计算,得出立体交叉分离型耦合器有最佳带宽特性的结论。文中也初步提出了实现宽带单模光纤定向耦合器的方法和设计步骤。     

一种改进的2×2 SOI Mach-Zehnder热光开关

本文设计并制作了基于强限制多模干涉耦合器的2×2 SOI马赫-曾德热光开关.这种光开关采用了深刻蚀结构的多模干涉耦合器和输入/输出波导,较大地提高了干涉耦合器的性能并减少了连接耦合损耗.同时,在调制臂区域采用浅刻蚀结构,保持其单模调制状态.深刻蚀多模干涉耦合器具有优越的特性,在实验中测得不均衡度只有0.03 dB,插入损耗－0.6 dB.基于这种耦合器的新型热光开关,其插入损耗为－6.8 dB,其中包括光纤-波导耦合损耗－4.3 dB,开关时间为6.8 μs.     

三种结构的光分插复用器特性比对研究

 针对电交换路由成为全光网通信和密集波分复用等高速信息传递网的电子瓶颈的现状,开展对全光光分插复用器的理论和实验研究。介绍了基于Mach-Zehnder干涉仪和FBG结构、基于FBG和光环行器结构以及一体化光纤光栅耦合器结构的光分插复用器的工作原理,实际构建了3种结构的光分插复用器,并分别搭建测试系统进行了单波长光信号上/下行实验研究,对比了这3种光分插复用器结构的性能和优缺点,为全光光分插复用器的设计制作提供了参考。     

Reconfigurable optical multiplexer based on liquid crystals for polymer optical fiber networks

In this work, different novel 3×1 multiplexer structures for being used in polymer optical fiber networks are proposed. Designs are compact, scalable, and of low consumption, capable of operating in a large wavelength range simultaneously 660, 850, and 1300 nm, due to the use of nematic liquid crystal cells. Light that comes from each input port is handled independently and eight operation modes are possible. Control electronics has been made using a programmable integrated circuit. Electronic system makes available the managing of the optical stage using a computer. An additional four optical sensors have been included for allowing the optical status checking. Finally, a polarization independent multiplexer has been implemented and tested. Insertion losses less than 4 dB and isolation better than 23 dB have been measured. In addition, 30-ms and 15-ms setup and rise times have been obtained. The proposed multiplexer can be used in any polymer optical fiber network, even in perfluorinated graded index one, and it can be specially useful in optical sensor networks, or in coarse wavelength division multiplexing networks.     

基于绝热孤子压缩效应的小基座孤子脉冲研究

高重复频率超短光脉冲产生技术是高速光时分复用(OTDM)系统的关键技术之一,而一般的超短脉冲源直接产生的脉冲往往不够窄,因此必须对光脉冲进行压缩后才能满足高速光通信系统的要求。采用360 m长的色散渐减光纤(DDF),成功将从再生锁模光纤激光器(RMLFL)输出的中心波长1546 nm、重复频率10 GHz、脉宽分别为5.40 ps和4.60 ps的光脉冲,绝热压缩为脉宽为1.93 ps和1.71 ps的小基座孤子脉冲,压缩因子分别为2.80和2.69。利用这种绝热孤子压缩方法得到的光脉冲质量较好,可以用于160 Gb/s的光时分复用系统。     

Generation of an arbitrary chirped microwave waveform with high time-bandwidth product for increasing range resolution of RADAR by using photonic technique

An approach for photonic generation of an arbitrary chirped microwave waveform with an increased time-bandwidth product (TBWP) is proposed and experimentally demonstrated. In the proposed model, light from the mode locked laser is splitted into two parts by using 1 × 2 power splitter: one is sent to linearly chirped fiber Bragg grating (LCFBG) through circulator and the other is time delayed by fiber delay line. The optical pulse in upper arm is time stretched by the LCFBG. Meanwhile, the optical pulse in lower arm experiences a time delay and then stretched by the dispersive single mode fiber. Temporal interference pattern is generated with an increasing or decreasing free spectral range by combination of two time-stretched optical pulses. Finally, the temporal interference pattern which is obtained at the output of optical coupler is transformed into an arbitrary chirped microwave waveform by using a photo-detector. The main advantage of this proposed model is high TBWP in the range of 750–1000 which ultimately results in an increased range resolution of radio detection and ranging.     

An optical OFDM multiplexer and 16 × 10 Gb/s OOFDM system using serrodyne optical frequency translation based on LiNbO3 phase modulator

This paper proposes an all-optical orthogonal frequency division multiplexing (OFDM) multiplexer based on sawtooth wave driving LiNbO₃ phase modulators by using serrodyne optical frequency translation. This multiplexer has high integration ability. The designing concept and implementation method have been discussed. A 16 × 10 Gb/s optical OFDM system is designed based on this multiplexer. Transmission characteristics, including tolerances of polarization mode dispersion (PMD) and nonlinear impairments have been studied numerically. Simulations show that the PMD tolerance is about 42 ps. The spectral efficiency reaches 1 bit/s/Hz with binary modulation format.     

波长可调谐超短光脉冲的简便高质的生成技术

提出了一种以处于增益开关调制状态下的法布里珀罗(Fabry-Pérot)半导体激光器作为光源,采用简单的自激注入锁定方式,以生成波长可调谐的超短光脉冲的实验系统。该实验装置中,激光器的外腔包括两个串联在一起的布拉格光纤光栅,一个掺铒光纤放大器(EDFA),一个光耦合器和两个环行器,其作用是选模,以及增强并控制反馈回激光器内腔的光强。该实验系统简单而高效,在24nm的波长调谐范围内获得了边模抑制比高于40dB的单模光脉冲输出;而在1521.8nm和1550.0nm之间28.2nm的波长调谐范围内,边模抑制比高于35dB。所得到的各个单波长激光脉冲的时域半峰全宽为140~260ps,各个脉冲的光谱半峰全宽皆为0.1nm。     

Dispersion compensation in optical transmission systems using high negative dispersion chalcogenide/silica hybrid microstructured optical fiber

In this paper, a new hybrid microstructured optical fiber (H-MOF) based upon photonic bandgap (PBG) light guiding mechanism which can be used for dispersion compensation in optical transmission systems is designed and simulated. The H-MOF core is made up of silica glass and the holes in the cladding network are filled with As₂Se₃ chalcogenide glass. By selecting an appropriate geometrical parameters for the structure, the dispersion and confinement losses of the proposed H-MOF at 1.55 µm are calculated to be ?6700 ps/nm/km and 6?×?10^?4 dB/m, respectively. Relative dispersion slope (RDS) of the H-MOF at 1.55 µm is about 0.00347 nm^?1. The proposed H-MOF is suitable for use in wavelength division multiplexing and dispersion compensating systems in optical fiber transmission networks.     

Multiple-Output Fiber-Ring Lasers and Amplifiers in a Hybrid CATV and ADSL Broadcasting Optical Fiber Communication System

In this article we propose two kinds of new fiber ring structure with a semiconductor optical amplifier. The first structure is a one-fiber-ring amplifier with an 8 × 8 fiber coupler and a semiconductor optical amplifier (SOA). The second fiber ring structure is a two-fiber-ring laser including an 8 × 8 fiber coupler, a 2 × 2 E/O modulator, and an SOA. The 14-output spectra of the fiber laser are measured. The gain coefficients of each port of the multiple-output-fiber-ring amplifiers are also measured. We apply these two kinds of fiber ring structures in a hybrid CATV and ADSL broadcasting optical fiber communication system. This application can develop a broadcasting system with large coverage area without using many laser diodes and optical amplifiers. The performance of such a system is also analyzed in this article.