共查询到20条相似文献,搜索用时 31 毫秒
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应用等效折射率模型研究光子晶体光纤 总被引:7,自引:4,他引:7
应用等效折射率模型研究了光子晶体光纤(PCF)的传播特性.介绍了光子晶体光纤的等效折射率模型.通过求解标量波动方程得到了光子晶体光纤包层基空间填充模的模式折射率,利用阶跃光纤的理论来研究光子晶体光纤的导模特性.应用此模型对不同结构光子晶体光纤包层区的等效折射率与波长的关系进行了讨论.包层区等效折射率与芯子的折射率差随波长的增加而增大,并由此阐述了光子晶体光纤的单模特性.数值分析得到光子晶体光纤的基模的模式折射率,并由此研究了光子晶体光纤的波导色散与结构参量的关系.分析表明,光子晶体光纤的波导色散随空气孔孔距的变化符合Maxwell方程的比例性质.空气孔的相对孔径对波导色散有重要的影响.这些分析表明光子晶体光纤具有可以灵活设计其色散特性的潜在应用前景. 相似文献
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This paper proposes a novel technique for automatic waveguide formation by means of the self-trapping effect of optical fiber irradiation into a photopolymerizing resin. We investigate experimentally the phenomenon of thin cladding layer formation surrounding the core following the core creation. In the proposed technique, a counterdiffusion effect involving polymerizing monomers via the core/cladding interface causes enrichment of a low refractive index monomer, and a resultant "W-shaped" refractive index profile is realized. The measured propagation loss of the fabricated waveguide is 1.7 dB/cm at 0.68 /spl mu/m wavelength. This technology is appropriate for the fabrication of large-core optical waveguides of greater than 0.5 mm in diameter and is useful for automating the optical fiber connection and packaging process by virtue of being an all-passive optically induced process. 相似文献
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Work on deposited glass waveguides on silicon to form waveguides and filters is reviewed. The choice of these particular waveguides makes sense only as part of a consistent approach to optoelectronic packaging. Hybrid optical packaging on silicon (HOPS) is described and briefly compared with other techniques. For these packages, two waveguides were developed: a tight mode waveguide with a silicon nitride rib core for matching a semiconductor laser and a loose mode waveguide with a phosphosilicate glass core for matching an optical fiber 相似文献
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包层空气孔孔径的不均匀性对微结构光纤非线性系数的影响 总被引:4,自引:3,他引:1
在基于微结构光纤(MOFs)的非线性装置中,光纤的非线性系数是一个很重要的参数,它受包层空气孔不均匀性的影响。用全矢量有限元法和误差理论分析了包层空气孔孔径的不均匀性对六角形高非线性微结构光纤非线性系数的影响。通过计算,得到了这种光纤HE1x1和HEy11模的非线性系数与每个空气孔孔径之间的关系,从而进一步得到了非线性系数的标准差与包层空气孔孔径标准差之间的关系。这样,在已知孔径的标准差时,很容易得到非线性系数的标准差。当孔径标准差与孔径设计值的比为5%时,HE1x1和HE1y1模非线性系数标准差与均匀孔径情况下非线性系数值的比分别为2.55%和3.06%。 相似文献
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Silica-air double-clad optical fiber 总被引:1,自引:0,他引:1
Kozlov V.A. Hernandez-Cordero J. Shubochkin R.L. Carter A.L.G. Morse T.F. 《Photonics Technology Letters, IEEE》2000,12(8):1007-1009
A new design of the silica-air double-clad optical fiber is proposed. The fiber was prepared from an MCVD preform inserted into a supporting silica tube with a fluorine-doped connective element with a lower refractive index (Δn~-4×10-3) and air as the second cladding. A numerical aperture as high as 0.3 was measured for the first cladding and for fiber lengths up to 50 cm. Although it is realized that the results are preliminary, the optimization of the fiber parameters promises a new all-glass design for double-clad optical fibers for high-power fiber laser applications 相似文献
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Index-guiding fibers presenting a Ge-doped photonic-crystal cladding and a pure-silica core are numerically studied for the development of efficient optical long-pass filters. They present a fundamental-mode cutoff (FMC) toward short wavelengths that leads to a high extinction ratio, sharp band edge, and bend-tunable transmission profile. The simple design poses no experimental challenge for fabrication and the relatively large obtained modal area makes these waveguides fully compatible with standard telecommunication fibers. The proposed long-pass filter compares favorably with standard, bulk, technology, and with a previously demonstrated photonic crystal fiber presenting a FMC. 相似文献
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Jaewang Yu Il-Bum Kwon Kyunghwan Oh 《Lightwave Technology, Journal of》2003,21(8):1779-1786
We report a thorough analysis on the Brillouin frequency shift as a function of geometrical parameters in a silica optical fiber consisting of triple-layered structure, GeO/sub 2/-doped core, P/sub 2/O/sub 5/, and F co-doped inner cladding, and pure silica outer cladding. General characteristic equations for the Brillouin frequency shift were analytically derived and analyzed for various fiber parameters. In experiments, three-layered optical fibers were fabricated and their Brillouin frequency shifts were measured in the wavelength region of 1.55 /spl mu/m by a pump-probe technique. The longitudinal acoustic velocity in each layer was found significantly affected by the thermal stress as well as the dopant concentrations. We confirmed both in theory and experiment that the inner cladding of a three-layered optical fiber does provide a new degree of freedom in precise control of the Brillouin frequency shift. 相似文献
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This paper describes a new theory of the maintaining force to keep the optical fiber in the ferrule hole, based on the theoretical analysis assuming the dimensional change among the ferrule, optical fiber, and epoxy adhesive layer, since the maintaining force is caused by the difference of linear expansion coefficients among those elements when temperature is changed. The major maintaining force for the optical fiber installed in the ferrule hole is caused by the radial compressive force applied to the cured epoxy adhesive layer, which caused by dimensional shrinking of the clearance between the optical fiber and the ferrule hole, due to a large amount of shrinkage in the ferrule and a small amount of shrinkage in the optical fiber when the temperature changes 相似文献
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Optical fibers with depressed claddings for suppression of coupling into cladding modes in fiber Bragg gratings 总被引:1,自引:0,他引:1
L. Dong L. Reekie J.L. Cruz J.E. Caplen J.P. de Sandro D.N. Payne 《Photonics Technology Letters, IEEE》1997,9(1):64-66
A new method for suppression of coupling from guided optical modes into cladding modes in an optical fiber Bragg grating using a fiber with a strongly depressed cladding is proposed. Strong suppression of the coupling has been demonstrated both theoretically and experimentally. 相似文献
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A new iteration technique has been proposed for calculating exact antiresonant values of cladding layer thicknesses in antiresonant reflecting optical waveguides (ARROW's). This technique enables design of ARROW waveguides with core layers incorporating sophisticated multilayer systems, where the approximate analytical formulas cannot be applied 相似文献
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Immonen M. Karppinen M. Kivilahti J.K. 《Electronics Packaging Manufacturing, IEEE Transactions on》2005,28(4):304-311
This paper describes the fabrication and characterization of optical/electrical printed circuit boards (O/E-PCB) with embedded multimodal step index (MM-SI) waveguides and integrated out-of-plane micromirrors (IMMs) for three-dimensional (3-D) optical interconnects. Optical circuitry is built up on PCBs using UV lithography; 45/spl deg/ input/output (I/O) couplers are fabricated by inclined exposure. Commercial polymers are used as optical core and cladding materials. Critical mirror properties of angle, surface quality, reflectivity, and coupling efficiency are characterized experimentally and theoretically. Optical and scanning electron microscopy, white light interferometry, and fiber scanning method are used in the investigations. Sloping profiles measured as a function of the incident light showed the attainment of mirror angles of /spl alpha/=36/spl deg/-45/spl deg/ with /spl plusmn/2/spl deg/ consistency. Near-field optical imaging with a white light source showed that out-of-plane beam turning was achieved. Topography investigations revealed a rectilinear negative tapering shape regardless of the incoming beam angle or type of substrate. However, higher substrate reflectancy was observed to lower the mirror angle. The average propagation loss measured for 10-cm-long waveguides at /spl lambda/=850 nm by the cut-back method was 0.60 dB/cm; the excess loss calculated for the mirror coupling was 1.8-2.3 dB. The results showed that the IMMs can be incorporated in O/E-PCBs to couple light in and out of planar waveguides. Furthermore, the presented results indicate that optical waveguides with integrated micromirrors for optical 3-D wiring can be produced compatible with volume manufacturing techniques. 相似文献
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Normalised parameter plots are given enabling prediction of propagation-constant perturbation in diffused optical waveguides due to a thick dielectric cladding. Refractive-index profiles of Gaussian and complementary-error-function form are treated. The variation of the number of propagating modes with time of diffusion is derived. 相似文献
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We report new methods to inherently increase the flatness and bandwidth of erbium-doped silica fiber amplifiers from three perspectives: fiber design, pump-signal WDM coupler optimization, and amplifier structure. First, to achieve inherent control of the gain spectrum, a new type of composite fiber structure with an Er-doped core and a Sm-doped cladding ring is proposed and experimentally demonstrated. Interaction of the optical field with the Sm-doped cladding to produce evanescent wave filtering is modeled, which provides an in-line control of gain fluctuation in the erbium-doped flier amplifier (EDFA) C band, 1530-1560 nm. Second, the effect of the spectral characteristics of WDM couplers over the L band of an EDFA is explored. A fused taper fiber coupler for a 1480-nm pump is optimized for signals in the wavelength range of 1570-1610 nm by measuring the small-signal gain, gain tilt, and noise figure in an L-band EDFA. Finally, a new all-fiber structure for a wide-band EDFA, where the L and C bands were coupled serially, is demonstrated with optimized pump-signal couplers. Further optimization of the new composite fiber structure and the transient effects in the serially coupled EDFAs are also discussed 相似文献
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Fang-Zheng Lin Yi-Jen Chiu Tsu-Hsiu Wu 《Photonics Technology Letters, IEEE》2007,19(5):276-278
The cladding layer effect on microwave propagation properties of semiconductor p-i-n waveguides is investigated in this letter. Through the optical excitation in quantum wells of p-i-n waveguides, high-speed photocurrent is used to examine the microwave propagation. Two devices of p-i-n waveguides with different cladding layers are fabricated and measured, showing that a higher speed is found in the waveguide of wider cladding width. Verified by the microwave propagation properties, the higher speed is mainly attributed to lower microwave propagation loss due to the lower impedance in the wider cladding layer, suggesting this kind of structure can be applied to high-speed waveguide-based devices 相似文献
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《Microwave Theory and Techniques》1986,34(4):453-456
Starting from the operating wavelength and the chemical composition of the materials that integrate the core and cladding of an optical fiber, a method was developed for the calculation of the values of the core radii; it allows fiber operation in a monomode region with minimum total dispersion. The study is restricted to step-index fibers and the selected theoretical model is based on the weakly-guiding characteristic equation. From these considerations it is possible to obtain two different values of core radii for a given source operating wavelength. The theory described allows the characterization of an optical fiber for use with a given light source and extends a previously described theory. 相似文献
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A directional coupler, consisting of two coaxial dielectric waveguides, has been studied as a possible fiber-optic sensor. The dependence of the power distribution between the guides as a functinn of the outer cladding index is considered for monochromatic illumination. The additional advantages of using wavelength modulation as opposed to intensity modulation are discussed, and the fiber design procedure is given in detail. Preliminary experimental results are presented for both systems, broadly consistent with theory but showing limitations caused by fabrication problems. The requirements for developing a practical device are considered. 相似文献