共查询到20条相似文献,搜索用时 0 毫秒
1.
Germania-glass-based core silica glass cladding single-mode fibers (/spl Delta/n up to 0.143) with a minimum loss of 20 dB/km at 1.9 /spl mu/m were fabricated by the modified chemical vapor deposition (MCVD) method. The fibers exhibit strong photorefractivity with the type-IIa-induced refractive-index modulation of 2/spl times/10/sup -3/. The Raman gain of 300 to 59 dB/(km/spl middot/W) was determined at 1.07 to 1.6 /spl mu/m, respectively, in a 75 mol.% GeO/sub 2/ core fiber. Only 3 m of such fibers are enough for the creation of a 10-W Raman laser at 1.12 /spl mu/m with a 13-W pump at 1.07 /spl mu/m. Raman generation in optical fiber at a wavelength of 2.2 /spl mu/m was obtained for the first time. 相似文献
2.
In this paper, a novel chalcogenide and silica photonic crystal fiber (PCF) structure is designed with circular air-holes located in the cladding and the various optical properties, namely, dispersion, nonlinearity and group velocity dispersion parameters are compared for two different core structures, namely, circular and octagonal. The objective is to obtain high nonlinearity with dispersion flattened PCF. The prime focus is to obtain high non-linear effects as it plays great role in speed and capacity of optical communications. The proposed chalcogenide octagonal and circular PCF exhibits a dispersion of +77.55 ps/(nm km) and +77.34 ps/(nm km), respectively, whereas, the nonlinearity is in the order of 4506 W−1 km−1 and 4498 W−1 km−1, respectively. Also, the silica octagonal and circular PCF exhibits a dispersion of +19.03 ps/(nm km) and +0.97 ps/(nm km) respectively, whereas the nonlinearity is in the order of 169.41 W−1 km−1 and 182.41 W−1 km−1 respectively. 相似文献
3.
Friebele E. Gingerich M. Long K. Levin P. Pinnow D. 《Lightwave Technology, Journal of》1983,1(3):462-465
The radiation-induced attenuation of pure silica core fibers measured at 0.85 μm has been reduced by treating the soot preforms in various oxidizing atmospheres; the most effective of the treatments used in this study was SOCl2 . Fibers treated in SOCl2 or Cl2 also have low OH contents. The radiation-induced loss of the treated fibers has been found to follow the square root of the drawing-induced absorption band height at 0.63μm. 相似文献
4.
设计了一种新型高温传感装置,将一段七芯光纤耦合在两段单模光纤之间,发射光进入到七芯光纤中,在透射光谱范围内产生周期性调制的超模干涉图案,其频谱偏移随温度变化而改变,实现了实时监测.该传感装置制造简单,实验证明在温度高达1000℃的环境下仍可稳定工作. 相似文献
5.
Dianov E.M. Grudinin A.B. Gurjanov A.N. Gusovsky D.D. Harutjunian Z.E. Ignatev S.V. Smirnov O.B. 《Lightwave Technology, Journal of》1992,10(2):118-124
The reproducible technology for producing high-birefringence fibers with stress-induced elliptical cladding and circular core is described. The authors have obtained fibers that have a birefringence of about (1-3) 10-4, a mode coupling parameter of about (2-7) 10 -5 m-1, and loss of less than 0.5 dB/km at 1.6 μm. The authors have found effects restricting the capability of test fibers to maintain the state of linear polarization 相似文献
6.
Kuwaki N. Ohashi M. Tanaka C. Uesugi N. Seikai S. Negishi Y. 《Lightwave Technology, Journal of》1987,5(6):792-797
The structural design, bending loss, and dispersion characteristics of the dual shape core (DSC) single-mode fiber with zero dispersion at 1.55 μm are described. It is clarified that the bending loss of the DSC fiber is less than one tenth of that of a step-index fiber, and that the dispersion sensitivity due to a small change of the core radius is less than half of that of a step-index fiber. The explanation for the small bending loss is presented. A greater reduction of bending loss is expected from the replacement of the center core profile with a Gaussian or triangular profile. 相似文献
7.
An attempt to relate polarization dispersion directly to some physical property and then use this as a means by which to characterize polarization-mode dispersion (PMD) is reported. A new diagnostic procedure has been developed and tested for screening dispersion-shifted (DS) fibers with PMD due to core ellipticity. Measurements of far-field radiation profiles across major and minor core axes are used to characterize polarization-mode dispersion. This technique is a relatively simple and quick method of screening dispersion-shifted fibers for polarization-mode dispersion greater than 5 ps/km. Differences in these far-field pattern widths were then correlated with direct core ovality measurements performed using the near-field refraction technique. The authors outline the test procedure in detail, analyze sources of error, and discuss detection limitations 相似文献
8.
Bending loss and impulse response of multimode fibers with graded-index core have been studied. A multimode fiber which has a large index difference is profitable because of low loss in bends. Impulse response of the fiber in which all of the possible modes are excited with the same intensity depends remarkably on the fourth-order term of the index profile. A small value of mode delay of 0.15 ns/km is estimated to be obtainable in a fiber having an optimum index profile and index difference ratio of 0.05 using incoherent light. 相似文献
9.
《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1986,74(10):1456-1458
The propagation characteristics of homogeneous single-mode optical fibers with eccentric core are analyzed by a numerical method based on the Improved Point-Matching Method (IPMM). The variation of fundamental mode propagation constant has been computed for various eccentricities with different fiber parameters. 相似文献
10.
针对一般红外光纤存在材料损耗高、制备工艺复杂、传输性能和输出光束质量差等问题,提出了一种适合CO2(二氧化碳)激光传输的新型大纤芯红外PBG-PCF(光子带隙型光子晶体光纤),该光纤由三角形结构光子晶体在中心抽掉19根毛细管空气孔形成大纤芯。利用PWM(平面波展开法)分析得到了传输波长为10.6μm的CO2激光的光纤带隙图;再利用基于全矢量有限元法的仿真软件COMSOL Multiphysics分析其损耗特性。结果表明,这种结构的PBG-PCF与现有的红外光纤相比,传输10.6μm CO2激光时的损耗更小,约为0.08dB/km,可满足医用传输大功率CO2激光的需要。 相似文献
11.
《Optical Fiber Technology》2013,19(1):31-34
Hollow core microstructured fibers whose cladding is composed by an elliptical arrangement of circular dielectric tubes are numerically investigated. Birefringence, differential group delay, and polarization dependent loss are evaluated for different values of ellipticity in order to quantify its effect on the two polarizations of the fundamental core mode. All these parameters have a minimum at the center of each transmission window and they assume maximum values at the edges. In particular, the birefringence goes always to zero irrespective of ellipticity. This proves that tube lattice fibers are strongly immune against unwanted core shape deformation, in particular when the working frequency is close to the center of the transmission windows. On the other hand they are not suitable to obtain polarization maintaining fibers. 相似文献
12.
随着智能手机、平板电脑等移动终端的出现,人们越来越倾向于使用方便易携的移动终端进行各项业务,导致了移动用户数量剧增。这对通信技术提出了更高的要求。如何在有限的网络资源中解决不断增加的用户数量而导致的各种通信要求的矛盾,是目前通信技术主要面临的考验。为了解决这一矛盾,进行网络优化势在必行,软交换技术作为通信网络发展的主要方向,本文主要研究了在软交换核心网下的网络优化相关问题。 相似文献
13.
In this paper, a temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers is proposed and demonstrated experimentally. The temperature sensing principle is analyzed and related experiment is performed. By controlling the core offset and splicing length of the specialty multi-mode fiber (SMMF), two sensors with different temperature sensing properties are obtained, and experimental results show that the temperature sensitivity can be up to 48.76 pm/°C in the range of 25—95 °C. Moreover, it has many advantages, including small size, high sensitivity, and simple structure. So it can be used in potential temperature sensing applications, such as industrial production, biomedical science, power electronics, and so on. 相似文献
14.
In this paper we discuss mode conversion in a straight fiber which maintains its circular cross section but whose radiusa(z) increases monotonically with the length coordinatez so that it passes from the single-mode to the multimode regime. Our principal concern is with step-index fibers which are treated in the scalar approximation. We study conversion of power from the incident dominant mode to other core and cladding modes for several functionsa(z) . The results of our calculations show clearly that the dominant mode is able to adapt itself to the changing fiber radius provided the change is gradual. For comparison, we also consider a fiber with an infinitely extended radial parabolic-index profile as an approximation to graded index fibers. We show that it too exhibits mode conversion similar to that of the step-index fiber, provided that the comparison is made on the basis of corresponding mode spot sizes instead of actual core radii. 相似文献
15.
We present empirical relations describing the spectral dependence of the spot sizes of the fundamental mode (along the major and minor axes) in a homogeneous elliptic core fiber. These relations are obtained by modeling the fundamental mode by a Gaussian distribution. Using these relations, we present a method for the determination of the equivalent step index (ESI) parameters of a monomode elliptic Core fiber. The applicability of the proposed method is shown through a) calculation of the cutoff wavelengths of a parabolic index elliptic core fiber and b) calculations of various fiber parameters like the core radii and index difference of an elliptic core fiber from recently reported experimental data. 相似文献
16.
Birefringence and polarization dispersion introduced by thermal stress in single-mode fibers with elliptical core are formulated here in terms of fiber structure parameters, thermal expansion coefficients, and thermoelastic constants. Thermal stress distribution and birefringence characteristics are estimated within first-order perturbation with respect to fiber core ellipticity. Normalized frequency dependence of birefringence and polarization dispersion is also derived in this paper. Birefringence and polarization dispersion in elliptical core fiber are seen to depend on thermal stress rather than geometrical anisotropy for relatively small relative index differences. Numerical examples are presented for germanosilicate, borosilicate, and phosphosilicate glass fibers. 相似文献
17.
A. A. Makovetskii A. A. Zamyatin G. A. Ivanov V. A. Aksenov 《Journal of Communications Technology and Electronics》2016,61(7):851-855
An original technique for manufacturing quartz optical fibers with an elliptical light-guiding core is proposed and tested. The dependences of the ellipticity of the light-guiding core on parameters of the manufacturing process—the temperature of the heating element of the high-temperature furnace and rarefaction inside the cylindrical tube preform—are studied. Test fiber samples are drawn and their optical properties are investigated. 相似文献
18.
Microbending losses in single-mode fibers with several types of core refractive index profiles are compared. Numerical calculations were carried out to characterize fibers with step, power-law,W and ring-shaped index profiles. Step-index andW fibers exhibit a small excess loss near the single-mode operation upper limit. However, permissible offset misalignment in fiber splice at constant microbending loss is nearly identical for step, power-law, andW fibers. An index dip at the core center has an undesirable influence on the required splicing accuracy. The effects of fiber curvature statistics and index profile parameters are investigated in detail. 相似文献
19.