大容量长距离传输用低非线性效应非零色散位移光纤

利用非等温等离子体化学气相沉积 (PCVD)工艺制备了一种适合于大容量高速率长途干线网与城域网的中芯下陷型纤芯结构非零色散位移光纤。该光纤的有效面积大于 95 μm2 ,在 15 5 0nm波段的色散值约为9ps/(nm·km) ,有效的抑制了传输过程中光非线性效应的产生。通过对光纤剖面结构的优化设计 ,光纤的 15 5 0nm处的传输损耗降到约 0 .2 1dB/km ,与传统单模光纤的熔接损耗低于 0 .11dB ,且在直径为 6 0mm圆筒上绕 10 0圈后在 14 6 0nm到 16 2 5nm波长范围所引起的附加弯曲损耗均低于 0 .0 2dB/km。同时 ,该光纤色散斜率低于0 .0 6 5 ps/(nm2 ·km) ,偏振模色散 (PMD)小于 0 .0 5 ps·km-1/2 。此外 ,由于光纤的零色散点移到了 14 30nm以下 ,使波分复用 (WDM)传输在S波段 (14 6 0～ 15 30nm)、C波段 (15 30～ 15 6 5nm)、L(15 6 5～ 16 2 5nm)波段上都兼容。     

Fabrication of low OH loss holey fibers with varying air hole sizes and their optical properties

We experimentally investigate a flexible fabrication technique for low OH and transmission losses holey fibers with a Ge-doped core and air holes in a silica cladding region. Versatile holey fibers of different size, pitch, and shape of air holes were achieved by controlling the temperature and heating time of the holey fiber preform. In addition, we suppress the OH loss of less than ∼0.323 dB/km at 1383 nm. After fabricating holey fibers, we measure their optical properties including cut-off wavelength, mode field diameter, splicing loss, dispersion, bending loss, and polarization dependent loss based on the size of air holes. The total transmission loss was measured to be ∼0.226 dB/km at 1550 nm by improving the fabrication process. After fabricating optical patch cord based on holey fibers, we measured the long-term stability of the fabricated holey fiber by using the temperature cycling technique for 24 and obtained low power fluctuation of 0.2 dB. We achieve the high quality holey fiber with a low bending loss of ∼0.04 dB/turn under a bending radius of 2.5 mm at 1550 nm. We also obtain a tunable band rejection filter with a number of bending turns.     

A Novel Fabrication for Method Long PeriodFiber Grating

A new method of fabricating all-fiber broadband-rejection filter based on long period fiber grating (LPFG) is proposed. The principle in the method is to make periodic asymmetrical deformation in the core of fiber without microbends by electrode discharging so as to induce periodic refractive index changes. Two kinds of filters whose rejection peak wavelength at 1550 nm and 1310 nm are obtained. The insertion loss is less than 0.6 dB and 1.4 dB respectively. The 20 dB bandwidth ranges from 10 nm to 39 nm. The backward reflection loss is extremely small (less than - 70 dB). Such devices can be used as isolation filters in 1310/1550 nm WDM system and other fields.     

A Novel Fabrication for Method Long Period Fiber Grating

A new method of fabricating all-fiber broadband-rejection filter based on long period fiber grating (LPFG) is proposed. The principle in the method is to make periodic asymmetrical deformation in the core of fiber without microbends by electrode discharging so as to induce periodic refractive index changes. Two kinds of filters whose rejection peak wavelength at 1550 nm and 1310 nm are obtained. The insertion loss is less than 0.6 dB and 1.4 dB respectively. The 20 dB bandwidth ranges from 10 nm to 39 nm. The backward reflection loss is extremely small (less than -70 dB). Such devices can be used as isolation filters in 1310/1550 nm WDM system and other fields.     

光波导-光纤自动调芯系统研究

设计了两种适用于光波导高精度自动对接耦合的调芯方案,从原理上克服了常规调芯过程中微变信号精确测试的困难。完成了调芯系统的光机电一体化、控制程序和接口界面。单模光纤作为标准波导的端面耦合自动凋芯试验显示,平均耦合损耗分别为0．075 dB(1310nm波长)和0．062 dB(1550nm波长),相应的标准误差分别为0．0099 dB和0．0066 dB．调芯过程在2min内完成。单模光纤-单模波导-单模光纤的对接耦合实验结果表明,端面耦合损耗平均值分别为0．140 dB(1310nm波长)和0．109 dB(1550nm波长),标准误差分别为0．0082dB和0．0107dB,调芯时间累计不超过8min。     

Fabrication of Variable Optica l Attenuator With Low Inse rtion Loss

Avoltage -controlled variabl optical attenuator (VOA) based on silica-b a sed planar ligh t wa ve circu its (P LC) was fabricated by flame hydrolysis deposition (FHD). The variable attenuator with Cr heater achieves 20dB attenuation with 318mW electrical power at 1550 nm. The insertion loss and the polarization dependent loss (PDL) at 0 attenuation are 1dB and 0.23dB, respectively.     

Polycarbonate hollow-core microstructured optical fiber

A hollow-core microstructured polymer optical fiber is fabricated from polycarbonate material and guidance by inhibited coupling in a two-layer structure is demonstrated in two strong transmission bands with minimum losses of 9.0 dB/m at 800 nm and 3.1 dB/m at 1550 nm. The latter corresponds to a loss well below the polycarbonate material loss at this wavelength, and to our knowledge it is the lowest loss hollow-core polymer fiber reported to date. The short-term operational temperature limit of the fiber is shown to be 135 degrees C, significantly higher than that of conventional polymer optical fibers made of other polymers.     

全玻璃实心保偏光子晶体光纤的研制

设计并采用棒管法结合毛细管堆积技术制备了一种全玻璃材料的实心保偏光子晶体光纤,光纤端面测试结果表明,这种结构设计有效克服了传统光子晶体光纤制造过程中空气孔易于塌陷的困难,光纤微结构保持良好.采用剪断法测得在1550nm波长下光纤的传输损耗为6.84dB/m.测试了输出光的偏振度,结果表明该光纤具有较好的保偏特性,说明采用此方法研制具有高保偏性能且制作工艺简单的光子晶体光纤是可行的.     

单模光纤窄带波分复用器的研究

由组合波导理论出发，分析了超长耦合器合区光纤间的功率耦合特性以及器件的偏振特性，并提出了研制二段窄波分单模光纤波发复用器的新方法，在研制常规耦合器的工艺基础上，先后研制成功１３１０ｎｍ或１５５０ｎｍ单窗口窄带波分复用器及１３１０ｎｍ或１５５０ｎｍ双窗口等三种复用间隔约１４ｎｍ的窄带波分复用器，其波长隔离度大于２０ｄＢ，具有２～３ｎｍ的带宽，偏振灵敏度小于０．１ｄＢ，附加损耗小于０．５ｄＢ，这些参数     

Design of a polarization splitter for an ultra-broadband dual-core photonic crystal fiber

A novel ultra-broadband polarization splitter based on a dual-core photonic crystal fiber (DC-PCF) is designed. The full-vector finite element method and coupled-mode theory are employed to investigate the characteristics of the polarization splitter. According to the numerical results, a graphene-filled layer not only broadens the working bandwidth but also reduces the size of the polarization splitter. Furthermore, the fluorine-doped region and the germanium-doped region can broaden the bandwidth. Also, the 4.78 mm long polarization splitter can achieve an extinction ratio of -98.6 dB at a wavelength of 1550 nm. When extinction ratio is less than -20 dB, the range of the wavelength is 1027 nm-1723 nm with a bandwidth of 696 nm. Overall, the polarization splitter can be applied to all-optical network communication systems in the infrared and near-infrared wavelength range.     

Tunable single- and dual-wavelength erbium-doped fiber laser based on Sagnac filter with a high-birefringence photonic crystal fiber

In this paper, we observed and experimentally investigated a high-performance single- and dual-wavelength erbium-doped fiber ring laser based on a Sagnac filter which contains a section of high-birefringence photonic crystal fiber (HB-PCF) and a polarization controller. Incorporation of the high-birefringence photonic crystal fiber can suppress multimode oscillation, improve power stability and increase the optical signal-to-noise ratio (SNR). Wavelength tunable was achieved by using a polarization controller in the Sagnac filter. Highly stable single-, dual-wavelength oscillations are tunable within a wavelength range from 1550 to 1562 nm and SNR as high as 57 dB with narrow line width about 0.011 nm, is experimentally demonstrated.     

双波长环形腔掺铒光纤激光器建模及模式竞争的仿真

利用Giles模型建立双波长环形腔掺铒光纤激光器模型,根据增益损耗匹配条件对1550 nm与1555 nm双波长的模式竞争进行了仿真。结果表明,在均匀增益加宽模型下,损耗谱的微小变化对激光的模式竞争过程有较大影响。当两模式各自的损耗与增益相匹配时,它们的输出功率相当; 但0.1 dB的随机损耗波动将导致两个模式输出功率的相对波动幅度分别达到9.59％和9.52％。当损耗长时间偏离匹配状态0.05 dB时,一个模式将逐渐减弱并最终湮灭,另一个模式得到增强。     

双尾纤式多功能光隔离器研究

提出并成功研制了一种具有功能复用的新型的多功能光隔离器结构, 对其进行了传输特性性能理论分析, 分析表明, 该器件具有与单尾纤光隔离器相同的低插入损耗, 高隔离度等特性, 实验结果显示,所设计的1550 nm双通道多功能光隔离器插入损耗分别为0.28 dB和0.11 dB, 隔离度分别为55 dB和54 dB, 达到了隔离器需要满足的标准, 性能良好, 同时具有成倍降低器件制造成本的效用.     

Diode-lasers based apparatus and method for single-mode fibers spectral splice loss measurements

Arc-discharge fusion splicing is widely used in the telecommunication industry for joining single-mode optical fibers to Er-doped fiber coils. These coils are used as the gain medium in erbium-doped amplifiers (EDFAs). The quality and integrity of splicing these coils to fibers can impact key EDFA performance parameters. This article describes an automated splice loss and Er-doped fiber absorption measurement system. The measurement system is equipped with 1310, 1550 and 1563 nm DFB lasers, broadband light source, InGaAs detectors and fiber-optic internal standards. Furthermore, the article describes a method for measuring splice loss between Er-doped fiber and the fibers spliced to coil ends. The system controls splice loss between SM-28 or HI980 fiber and Er-doped fiber to 0.094 ± 0.052 dB at 1550 nm. Moreover, the system can measure accurately Er-doped fiber absorption to within ±3.19% at 1563 nm.     

Polarization rotator for InP rib waveguide

A polarization rotator, suitable for integration in a polarization diversity optical receiver fabricated in InP technology, is proposed. The device, based on a two steps waveguide rotator, includes tapered input and output ports that provide very low insertion loss (<0.04 dB). An extinction ratio of 40 dB at 1550 nm wavelength is calculated, comparable or even superior to other state of the art polarization converters. The main advantage of the proposed design is the capability of implementation using a standard fabrication process with only two dry etch steps, significantly reducing complexity and cost.     

Stable dual-wavelength erbium-doped fiber laser using novel fabricated side-polished arc-shaped fiber with deposited ZnO nanoparticles

A dual-wavelength fiber laser operating at the 1550 nm region using a side-polished arc-shaped fiber with deposited ZnO nanoparticles is proposed and demonstrated. The arc-polished fiber is fabricated by using a simple but novel approach in which a silicon carbide paper polishes one side of a conventional single-mode fiber. An arc-polished fiber with a length of 2.25 mm and an insertion loss of 0.95 dB is obtained and deposited with ZnO nanoparticles by the drop-cast method. A stable dual-wavelength output is obtained at 1562.5 and 1563.4 nm at peak powers of-9.3 and-10.1 dBm, respectively, as well as a signal-to-noise ratio of 28.4 dB and a channel spacing of 0.9 nm. Both lasing wavelengths also have narrow linewidths of between 0.045 and 0.049 nm and show little to no wavelength or power fluctuations over continued testing.     

In-fiber polarizer based on a long-period fiber grating written on photonic crystal fiber

A novel in-fiber polarizer based on a long-period fiber grating (LPFG) is written by using a focused CO2 laser beam to notch a photonic crystal fiber periodically. Such a polarizer exhibits a high polarization extinction ratio of more than 20 dB over a wide wavelength range of ~11 nm near 1550 nm and a very low temperature sensitivity of 3.9 pm/ degrees C, which overcomes the disadvantages of the temperature sensitivity of other in-fiber polarizers created on conventional single-mode fiber.     

Efficient broadband silicon-on-insulator grating coupler with low backreflection

We design and fabricate an efficient broadband grating coupler on a 400 nm thick silicon-on-insulator wafer. The measured coupling loss is 3 dB when coupling to a single-mode fiber at 1310 nm wavelength with TE polarization. The spectral FWHM and backreflection are determined to be 58 nm and -27 dB, respectively.     

含氟聚酰亚胺波导波长分离耦合器优化设计

提出并采用统计优化的设计方法解决含氟聚酰亚胺波导波长交叉分离耦合器的偏振态变动的影响.在实测了含氟聚酰亚胺的色散和双折射特性的基础上,优化设计了40路波长信道、1550 nm中心波长、0.8 nm波长间隔的抗偏振变动的波长交叉分离耦合器.数值模拟显示:波长周期偏移小于0.1 nm,1 dB带宽为0.5 nm,3 dB带宽为0.8 nm,串扰小于－30 dB,偏振变动导致的波长漂移小于0.08 nm.     

Long-Distance Transmission of AM-VSB CATV Systems Using Fabry-Perot Laser Diode and Fiber Bragg Grating

This study presented a directly modulated 1550 nm NTSC AM-VSB CATV longdistance transmission system using Fabry-Perot laser diode, optical isolator, fiber Bragg grating, quarter-split-band, and wavelength-division multiplexing techniques. Good carrier-to-noise ratio ( ≥48 dB), composite second-order ( ≥64 dB), and composite triple-beat ( ≥60 dB) performances were obtained after a 100 km standard single-mode fiber transmission. Our proposed system does not use an externally modulated 1550 nm transmitter and a sophisticated stimulated Brillouin scattering suppression technique. It reveals a prominent technique with simpler and more economical advantages than that of externally modulated 1550 nm transmission system.