基于宽谱信号光注入的超荧光光纤光源

为实现高功率和高平坦度的C+L波段光超荧光输出,将超辐射发光二极管输出的宽谱信号光注入双程后向掺铒光纤超荧光光源,研究了信号光注入对超荧光光源输出功率和光谱特性的影响,优化了信号光注入功率、泵浦源抽运功率和掺铒光纤长度。结果表明:低功率、宽光谱信号光不仅可以有效提高超荧光光源的输出功率和泵浦效率,还有助于光谱的平坦化;通过使用40m W抽运功率泵浦9m的掺铒光纤,在500W信号光注入时获得了功率为10.59m W、3d B带宽大于41nm的C+L波段超荧光输出。     

基于光纤环形镜的C+L波段高平坦高功率掺铒光源

研究并设计了一种用3 dB宽带耦合器制作的光纤环形镜作为反射镜的双级双程单管抽运高平坦度高功率C+L波段ASE光源。用2个980 nm激光二极管调试两级抽运光功率的分配,两级采用掺铒浓度不同的光纤并优化光纤长度,获得了功率高达15.28 mW(11.84 dB/m)的C＋L波段ASE光输出,平均波长为1 559.31 nm,在未采用任何外加滤波器的情况下,其平坦区域3 dB带宽66.72 nm(从1 533.12 nm至1 599.84 nm)。之后采用一个激光二极管实现两级双向同时抽运得到了同样的效果。通过光纤环形镜的使用,不仅提高了抽运源利用效率,且改善了光源的平坦度,在实验过程中,在平坦度相度相对要差一些的条件下,还通过调整两级抽运光的功率及分配比例得到了功率达到30.11 mW的C+L 波段ASE输出。     

用于高精度光纤陀螺的掺铒光纤宽带光源的优化

为优化双程后向结构的掺铒光源,分析了光纤长度、泵浦功率和温度的变化对光源平均中心波长的影响,初步确定了掺铒光纤长度的优化范围,并在全温度范围内进行实验验证。实验选用的980nm泵浦源电流为110mA,掺铒光纤的长度为12.5m,该装置的输出功率为13.26mW,光源的平均波长稳定性为0.6℃-1。通过建立光谱分布优化仿真模型,实现输出光谱的近高斯分布,3dB带宽达到32nm。经过优化后得到的掺铒光纤光源具有输出功率高、平均波长稳定性好、输出光谱呈高斯分布等优势,是高精度光纤陀螺的理想光源。     

机械感生长周期光纤光栅的可调谐环形光纤激光器

将采用机械感生法写制的长周期光纤光栅(MLPFG)串入环形腔中,设计了一种新颖的L波段可调谐环形掺铒光纤激光器(EDFL)。抽运光源为980nm半导体激光器,使用掺铒浓度为5×10-4,长度为12m的铒纤作为增益介质,通过调整待写制光纤与周期性压力槽之间的夹角,改变MLPFG的写制周期,调谐MLPFG透射谱,进而影响环形腔增益最高点,光纤激光器波长可调谐范围可达42nm(1562.465～1604.280nm),激光光谱3dB带宽0.04nm,20dB带宽0.08nm,边模抑制比45dB。长时间观测表明,激光功率稳定性优于0.2dBm。实验显示,该光纤激光器具有带宽较宽,线宽较窄及性能稳定等特点。     

基于FBG的波长可调谐环形掺铒光纤激光器

在介绍光纤光栅波长调谐原理的基础上,设计了一种环形腔掺铒光纤激光器。利用光纤光栅(FBG)作为波长调谐元件,在20~170 ℃的温度范围内,实现了输出激光波长在1 547.7~1 556.5 nm内的连续可调,调谐线性度达99.96%,激光光谱的3 dB带宽均小于0.05 nm,20 dB带宽均小于0.08 nm,边模抑制比大于52 dB,输出功率可达21.2 mW。结果表明:可调谐掺铒光纤激光器具有可用带宽较宽、功率高、线宽窄、与光纤元件天然兼容等优点。     

掺铒光纤超荧光光源外部增益平坦技术的研究

为满足光纤布拉格光栅传感和波分复用光纤通信系统对光源光谱平坦度与带宽的要求,利用外部增益平坦技术实现掺铒光纤超荧光光源输出光谱的平坦化。介绍了三种常见的外部增益平坦技术,并通过实验对平坦结果进行比较,由此得出采用长周期光栅增益平坦滤波器是一较好的选择。实验结果表明,平坦波段范围内(1 525~1 540nm)的光谱不平坦度小于±1.1dB,整个C波段光谱的3dB带宽为39.125nm。     

可调谐锁模光纤激光器泵浦的超连续谱光源

为了实现平坦度更好、光谱覆盖可见光波段的超连续谱激光输出,研究了泵浦波长可调谐的全光纤结构超连续谱光纤激光器。设计搭建了一台非线性偏振旋转锁模脉冲光纤激光器,实现了9种中心波长的耗散孤子皮秒脉冲输出,波长调谐范围为1 041~1 076nm;以它作为种子源进行了两级功率放大,并泵浦10m长的光子晶体光纤,在泵浦激光功率为500mW时,得到9种输出光谱特性不同的超连续谱激光,得到当泵浦激光中心波长为1 050nm时,更利于实现光谱范围更宽、平坦度更好、可见光分量更多的超连续谱激光输出。为进一步拓宽超连续谱激光的光谱范围、提升光谱平坦度,将泵浦激光功率提升至1.45 W,最终实现了输出功率为600mW、短波边界为470nm、600~1 700nm内10dB光谱宽度为1 053nm的超连续谱激光输出。     

光纤CATV网络高性能EDFA的研制

介绍了采用980nm和1480波长泵源双向泵浦结构，研制输出光功率大于22dBm、噪声系数低于5dB的光纤有线电视网络掺铒光纤放大器的基本原理、优化方案和实验结果。     

980nm高稳定度激光泵浦源控制系统

设计、制作了一款980nm高稳定度激光泵浦源控制系统,以满足掺铒光纤放大器(EDFA)稳定工作的需要。首先,以恒流激励原理设计了控制系统的驱动单元。接着,使用半导体制冷器(TEC)作为泵浦源的温度控制手段,设计了控制系统的温度控制单元。为了验证控制系统的有效性,选用一款激光泵浦模块组成了完整的激光泵浦源系统。最后,对激光泵浦源的激光输出进行了实验,研究了光功率与驱动电流的关系,以及系统的光功率稳定度与光谱稳定性等。对系统进行了相关测试实验,结果显示:应用了本控制系统的激光泵浦源的激光输出中心波长为975.2nm,光功率可达600mW,短期光功率稳定度为±0.008dB,长期光功率稳定度为±0.05dB,比同类激光泵浦源具有更高的稳定度。得到的结果表明:所设计的激光泵浦源控制系统满足设计要求,具有一定的实用价值。     

Er3+/Yb3+共掺双包层光纤的高功率L-band 光纤激光器的实验研究

采用端面泵浦的方式,用尾纤输出波长为976 nm的高亮度多模半导体激光器, 包层泵浦的铒镱共掺双包层大模面积光纤,非球面镜组耦合系统,进行了共掺双包层光纤的高功率L-band光纤激光器的研究,泵浦耦合效率达到了62%以上,并在F-P激光振荡腔中实现了高效的连续激光输出。在光纤长度为30 m、入纤功率为 13.41 W时,首次报道输出连续功率达到了4.3 W。激光器的斜率效率为44％, 激光输出中心波长1 603 nm。     

All-fiber Mach–Zehnder comb filter based on tapered fibers for wavelength switchable erbium-doped fiber lasers

Abstract

A wavelength switchable erbium-doped fiber laser was constructed based on an all-fiber Mach–Zehnder interferometer (MZI) comb filter. The MZI consisted of a fiber with two tapers. An L-band erbium-doped fiber was used as the gain medium, and 1557.92, 1563.2, and 1568.06?nm single-wavelength and dual-wavelength switchable lasers at 1558, 1563.7, and 1570.2?nm were realized by adjusting the polarization controller. During scanning, the maxmin power fluctuations of single- and dual-wavelength lasing were 0.604 and 2.482?dB, respectively. The signal-to-noise ratio was >24.46?dB and the laser’s 3?dB linewidth was <0.39?nm.     

掺铒单模光纤飞秒脉冲激光器和放大器

为了获得一种被动锁模掺铒光纤振荡器及功率放大器，数值模拟出超短脉冲在光纤中的传输和演化过程，并基于此搭建了一种被动锁模掺铒光纤飞秒振荡器及功率放大器。实验获得了中心波长1560 nm、重复频率100 MHz、输出功率30 mW、脉冲宽度85 fs超短脉冲。通过采用PPLN晶体进行倍频，进一步获得了输出功率5 mW，中心波长780 nm的飞秒脉冲。该光纤激光器为全保偏光纤结构，具有体积小巧、可靠性高、稳定性好的特点。     

重复频率锁定的783 nm飞秒光纤激光器研制

设计并搭建了重复频率长时精确锁定的783 nm飞秒光纤激光器。该激光器基于全保偏非线性干涉环镜(NALM),实现掺铒光纤振荡器锁模脉冲输出,由与脉冲分离器级联的环境稳定掺铒光纤双级放大器进行功率放大,实现了平均功率1.30 W、脉冲宽度130 fs、重复频率77.1 MHz、1560 nm脉冲输出;通过周期极化铌酸锂(PPLN)光学晶体倍频,获得了平均功率为0.52 W、脉冲宽度为140 fs、783 nm脉冲输出。通过重复频率监测及锁相环技术,进一步将掺铒光纤振荡器的重复频率溯源至参考铷原子钟,12 h内频率抖动峰-峰值为5 mHz、标准偏差为1.2 mHz。该激光器系统具有稳定性高、集成度高、体积小的特点。     

A lensed fiber workstation based on the elastic polishing plate method

Integrated coupling between laser source (such as laser diodes, LD’s) and single-mode fibers (SMFs) is one of the most important and fundamental techniques of optical communications. Lensed fibers have desirable features for the coupling scheme, such as compactness, simplicity, stability, and freedom from bulky lenses. However, the high precision lens geometry is required for lensed fibers. In this study, we present a lensed fiber fabrication workstation based on the elastic polishing plate mechanism. A theoretical model was also proposed in order to simulate the fiber lapping condition. The results show that the lensed fiber’s dome radius is mainly controlled by the accumulated lapping time, Preston’s coefficient, and selection of rubber pad material. The lapping time control is demonstrated as a preferred working parameter and thus is implemented in our fiber workstation.     

Wavelength switchable and stable single-longitudinal-mode erbium-doped fiber laser based on Mach–Zehnder interferometer and tunable filter

An erbium-doped fiber laser with all-fiber Mach–Zehnder interferometer (MZI) and tunable filter was proposed and experimentally demonstrated. In the designed fiber laser, 6?m C-band erbium-doped fiber was selected as a gain medium; the MZI comprised two waist-enlarged fiber bitapers. In the experiment, the laser threshold was 93?mW, whereas a switchable single-longitudinal-mode laser was realized within 1519.7–1564.6?nm by adjusting the tunable filter and the line interval was less than 2.5?nm; for single-wavelength laser, the peak power difference of each line was less than 4?dB, and the power fluctuation was less than 0.77?dB within 10-min scan time. A stable and switchable dual-wavelength laser was realized, the wavelength spacing of each dual-wavelength laser was less than 0.7?nm, the side-mode suppression ratio was more than 30.2?dB, and the power shift was less than 0.39?dB. The laser’s 3-dB linewidth was less than 0.1?nm.     

Lensed plastic optical fiber with an aspherical fiber end formed by joining an aspherical plastic lens and a plastic optical fiber using laser transmission welding

In optical communication systems which require the coupling of the light source to the fiber, efficient coupling can be practically realized either using a separate lens or by direct formation of the lens at the fiber end. A novel lensed plastic optical fiber (LPOF) is presented with efficient coupling of the plastic optical fibers with a light source. An aspherical plastic lens was bound with a flattened plastic fiber end by laser transmission welding (LTW) to form an aspherical fiber endface which can provide better coupling efficiency than a spherical fiberface. An analysis demonstrates that LTW can offer strong welding with small heat affected zones that are appropriate for commercial use. In this study a useful method for manufacturing lensed-end fibers is developed and demonstrated experimentally.     

光纤放大器的应用进展

光纤放大器的出现解决了衰减和损耗对光网络传输速率与距离的限制.掺铒光纤放大器(EDFA)的使用,使超高速、超大容量、超长距离的波分复用传输、全光网络传输、光纤有线电视(CATA)系统、光孤子传输等成为现实.