共查询到20条相似文献,搜索用时 46 毫秒
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为了实现光纤激光器和放大器系统中不同参量光纤的低损耦合,采用光纤拉锥方法来实现光纤连接。经过理论分析,在大数值孔径光纤传输到小数值孔径光纤时,采用光纤拉锥技术可以有效地提高传输功率。采用改造的大模光纤熔接机进行拉锥实验研究,精确控制拉锥时间、放电功率、步进量和步进速率可以获得不同的拉锥形状。采用光纤拉锥元件对标准单模光纤和大模场光纤进行耦合实验,得到纤芯内传输的耦合输出效率由之前的50%提高到85%,获得了低损连接效果。结果表明,熔融拉锥技术为不同光纤之间的耦合提供了一种简单实用的方式。 相似文献
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锥形光纤的结构与特性 总被引:1,自引:0,他引:1
通过理论分析和仿真试验,研究了锥形光纤的几何形状对锥形光纤的传输损耗和耦合效率的影响.用几何光学的分析方法,说明了光信号在锥形光纤中的传输损耗远低于同类型的圆柱形光纤;仿真试验研究了光源与光纤的相对位置、锥形光纤的尖端半径、锥形光纤的锥角大小对锥形光纤耦合效率的影响. 相似文献
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《中国激光》2010,(10)
锥形光纤是直径沿轴向逐渐变化的一种光纤。使用broyden迭代结合打靶法求解了基于熔融拉锥光纤布拉格光栅(FBG)的耦合模方程,数值分析了光纤轴向上的锥度对FBG光谱的影响。与未拉锥的均匀FBG相比,锥形光纤的FBG光谱向短波长处漂移,光谱带宽增大。由于纤芯束缚光场能力变弱,光谱的峰值反射率和透射深度均减小。锥度越大,这种现象越明显。实验中使用拉锥方法制作锥形光纤,通过在相同拉锥长度的情况下改变拉锥速度得到不同锥度的光纤,研究了锥形光纤损耗与拉锥速度的关系。使用波长为248 nm的紫外激光和周期为537 nm的均匀掩模板在所制作的锥形光纤写入布拉格光栅,研究了不同锥度光纤对光栅光谱的影响。实验结果与理论分析结果基本吻合。 相似文献
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基于光在熔锥光纤中传输的基本原理,分析了在外界温度不断变化的情况下涂覆折射率匹配液的熔锥光纤传输损耗特性。利用计算机仿真与实验得到了这种器件的传输损耗特性曲线,计算机仿真结果和实验结果的一致性很好地说明了熔锥光纤传输特性随温度变化的关系。随着外界环境温度的升高,折射率匹配液的折射率降低,熔锥光纤所携带的光功率占总光功率的比值增加,导致传输损耗减小。同时利用这种传输特性得到了一种温度可调的短通滤波器件,在一定温度下,这种滤波器对长波的滤波大于35dB,其滤波截止波长随温度升高而向长波方向漂移,温度系数是40nm/℃。 相似文献
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多粒子散射的偏振传输特性分析 总被引:6,自引:1,他引:6
针对多因素影响下偏振光在散射介质中的一般传输特性,系统分析了入射光波长、介质厚度、粒子参数和入射光偏振态等物理属性对偏振光子传输特性的影响。采用蒙特卡罗方法,追踪每个光子的偏振态变化,通过统计分析偏振度变化曲线得到光经过多次散射后的斯托克斯矢量和偏振信息,并对偏振光在散射介质中的传输规律进行分析。仿真实验表明相对于波长比较大的粒子对入射光的偏振态改变较小;线偏振光能较好地保持自身偏振态;圆偏振光能够在较短时间内重新恢复自身偏振状态,粒子半径越大恢复能力越强,并且在向前传输的过程中其旋转方向会发生改变。 相似文献
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Driver stages in MOS circuitry have been extensively investigated during the last decade. recently a tapering rule for CMOS buffers was derived showing that the tapering factor (β) is determined by the ratio of output to input capacitance. The derivation fails to account for the correlation between the short-circuit current and β. As a result, the derived formula consistently overpredicts the value of optimum β, especially for large input/output capacitance ratios. The authors present a modified formula and a method to account for the effect of the short-circuit current that is viable for buffer stages over a wide range of output/input capacitance ratios; this newly derived formula accurately predicts the optimum tapering factors for BiCMOS as well as CMOS buffer chains 相似文献
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Jaeger's buffer comprises a string of tapered inverters. Each inverter is molded by a capacitor and a conductor. In this work, the capacitor is split into inherent and load components (C x and C y), and it is shown that the value of the optimal taper depends on the C x/C y ratio: the best taper exceeds Jaeger's 2.72 slope, but only moderately 相似文献
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Adiabatic fused tapered couplers 总被引:1,自引:0,他引:1
Pre-fattening of one fibre is shown to be a vehicle for achieving wavelength independent adiabatic fused tapered couplers. Compared with the conventional pre-tapered fused tapered coupler, this adiabatic coupler has a significant improvement in its ease of manufacture 相似文献
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Coaxially-fed tapered slot antenna 总被引:1,自引:0,他引:1
An improved design of the longitudinal tapered slot antenna is presented which incorporates a tapered coaxial line balun. This transformer type offers large bandwidth, allows for the direct connection of coaxial sources and reduces the complexity of the printed circuit. Experimental results for an antenna prototype are presented 相似文献
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A switched band antenna that has a capability to operate in dual-band WLAN mode (2.4-2.485 GHz and 5.725-5.875 GHz), a single band WLAN mode of 2.4-2.485 GHz and a wideband mode (2.2-7.2 GHz) is presented. The antenna is based on a tapered slot antenna, which has a defected ground structure containing two switchable ring and two rectangular slots to provide a switched band property. Measurement results on a prototype antenna, with an ideal switch, fully demonstrate the performances of the proposed designs. The proposed antenna is suitable for use in a base station or an access point for WLAN and wideband applications and may be also useful in future multimode radio systems. 相似文献
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The primary packaging of singlemode tapered couplers, by fusing the fibre leads with a negligible loss to a silica substrate, is reported. This procedure eliminates adhesive, and ensures matched coefficients of thermal expansion throughout.<> 相似文献
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Mode coupling in tapered structures 总被引:2,自引:0,他引:2
The theory of strong mode coupling involving nonorthogonal modes is extended to tapered structures. Initially, an attempt is made to show that previous formulations of the problem of nonorthogonal-mode coupling in tapered structures are incomplete. An equation is derived which is the generalization to tapered structures of the coupled-mode formalism with nonorthogonal modes 相似文献
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Broadband tapered microstrip leaky-wave antenna 总被引:1,自引:0,他引:1
Wanchu Hong Tai-Lee Chen Chi-Yang Chang Sheen J.-W. Yu-De Lin 《Antennas and Propagation, IEEE Transactions on》2003,51(8):1922-1928
This study proposes a novel scheme based on the characteristics of leaky-wave antennas for the empirical design of broadband tapered microstrip leaky-wave antennas. This scheme can explain and approximately model the radiation characteristics of a linearly tapered leaky-wave microstrip antenna. A broadband feeding structure that uses the balanced and the inverted balanced microstrip lines to form a pair of broadband baluns is also presented. The measured return loss of the inverted balanced microstrip lines has a VSWR/spl les/2 from dc to 18.6 GHz and that of the back-to-back feeding structures has a VSWR/spl les/2 from 2.2 to 18.6 GHz. This feeding structure can be used to feed a broadband planar leaky-wave antenna with a fixed mainbeam that uses the tapered microstrip structure. The measured bandwidth of the antenna for a VSWR/spl les/2 exceeds 2.3:1. 相似文献
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Beam radiation from tapered waveguides is studied theoretically using the intrinsic mode approach. The field distribution across the beam, beam width, and angle made by the beam with interface to the tapered waveguide substrate, important parameters in coupling devices, are studied. Finally, some of our theoretical results are compared to measurements made on optical coupling devices. 相似文献
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A technique for synthesizing a resistive taper that generates desired bistatic scattering and backscattering patterns from a strip is outlined. Antenna synthesis techniques relate the scattered field to the induced surface current density. Physical optics approximations then relate the induced current to the resistivity. The taper is checked by computing the surface current density and scattered fields of the tapered resistive strip using the integral equation formulation and comparing with the physical optics results. 相似文献