共查询到20条相似文献,搜索用时 15 毫秒
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Sunil K. Khijwania Frances D. Carter John T. Foley Jagdish P. Singh 《Fiber and Integrated Optics》2013,32(1):62-75
Abstract This article investigates optical power transmission characteristics with varying launching conditions concentrating on weakly guiding, step-index highly multi-moded optical fibers. A single analytical expression for the fractional power transmitted per mode in a highly multi-moded fiber is obtained. This expression is used to numerically obtain the fractional power per mode, power per modal order, and finally, the total power carried by the fiber. Experiments are carried out to investigate the effect of launching conditions on the total power carried by the fiber and to establish a possible correlation with the theoretical results. Reasons for the observed experimental discrepancies are also discussed. 相似文献
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We propose a new method for fabricating optical waveguides with nonuniform thickness by controlling the electrical field distribution during the field-assisted ion-exchange. We refer to this method as distributed-fild-assisted ion-exchange. The distribution of the intensity of the electrical field was simulated for different electrode configurations, and was compared with experimental diffusion depth distribution of K+—Na+ exchange in sodalime slide glass. A unique bath was designed for the distributed-field-assisted ion-exchange. Using a three-electrode configuration, we obtained, for instance, a 2 cm-long spot size converter with thickness changes of from 12 μm to 2 μm. This technique can be used to fabricate waveguides for optical chemical sensors.On leave from State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing, China 100080. 相似文献
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随着光通信技术的不断发展,光纤的应用越来越广泛,而锥形光纤以其独特的传光方式越来越多地应用于光纤连接、成像及测量等领域。实验测定了不同锥角和不同长度锥形光纤的偏振特性。理论上,根据麦克斯韦方程组以及边界条件给出了光在理想光纤中的场分布,阐明了实际光纤中光的传输特性。论证了锥形光纤长度与其偏振特性的关系,进而利用几何光学方法对锥形光纤锥角与其偏振特性的关系作了定性说明。并用具体数据进行了定量计算,得出偏振光经锥形光纤传输或耦合后再传输到其终端所得到均是椭圆偏振光的结论。 相似文献
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基于多模光纤滤波器的可调谐掺铒光纤激光器 总被引:1,自引:0,他引:1
研究了一种新型、全光纤、宽带可调谐环形腔掺铒光纤激光器。该激光器利用由单模-多模-单模光纤组成的滤波器实现波长可调谐及激光器的全光纤结构。该滤波器将多模光纤缠绕在偏振控制器上,两端分别与一段单模光纤相连,通过调整偏振控制器的状态,实现了中心波长1542~1560nm的不同激光输出。单波长连续可调谐激光器的波长可调范围为18nm,边模抑制比大于40dB,3dB线宽为0.096nm;进一步调整偏振控制器的状态和抽运功率,实验同时得到了连续可调谐的双波长、三波长等多波长激光输出。对于可调谐的多波长激光器,通过调整偏振控制器的状态,可实现波长间隔及输出中心波长两者可调。 相似文献
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This paper describes theoretically one of the physical phenomena that take place in a tapered single-mode optical fiber (taper): the transfer of optical power between different order modes. This optical power transfer depends on several factors; one of them is the static bending of the taper, as other authors have reported. In addition to these studies, we have noticed that if the bend angle oscillates, then the magnitude of the optical power transfer is also modified by other additional factors. Thus, at dynamic conditions the transmitted optical power through the taper is also affected by the oscillation frequency. Here we propose a more generic equation system to obtain the coupling coefficient between modes under static as well as dynamic bending conditions. When the presented equations are particularized for static conditions, a complete agreement with other studies is observed. In addition, validating the theoretical justification, some experimental results are also shown. 相似文献
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We describe the operation and performance of an optical fiber trap realized using a tapered hemispherically lensed optical fiber. Axial and transverse trapping forces exerted on a microsphere are experimentally analyzed to corroborate the optical trapping using an optical fiber. Experimental results are as follows. (i) Transverse force Ftr acting on a sphere is a restoring force that acts to pull the microsphere back to the center of trap. (ii) Axial force Fax always acts to push a sphere in the direction of the beam away from the trapping fiber end. (iii) Vector sum of Ftr and Fax acting on a sphere gives a restoring force directed back to the stable point. (iv) Transverse force Ftr plays a significant role in trapping a micro-sized object by means of an optical fiber.This paper was originally presented at the 5th International Conference on NEAR FIELD OPTICS and RELATED TECHNOLOGIES (NFO-5), which was held on December 6–10, 1998 at Coganoi Bay Hotel, Shirahama, Japan, in cooperation with the Japan Society of Applied Physics and Mombusho Grant-in Aid for Scientific Research on Priority Areas “Near-field Nano-optics” Project, sponsored by Japan Society for the Promotion of Science. 相似文献
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自聚焦透镜的光斑尺寸与像差特性分析 总被引:1,自引:1,他引:1
对自聚焦透镜的光斑尺寸和像差特性进行了理论分析.利用自聚焦透镜光斑测量系统对样品的出射光斑进行了扫描,测得了光斑的大小;用读数显微镜和正方形网格图分别测量了样品的球差和畸变,并对光斑的测量作了误差分析,讨论了球差与畸变、光斑和像差之间的关系.所得结果对光斑质量的改善、像差特性的研究和自聚焦透镜的评估有一定的参考价值. 相似文献
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本文从计量检定角度提出一种光纤损耗测试仪的校准方法。利用光纤衰减器、Y型光纤分路器及标准光功率计,可评价损耗测试仪的精度等级。方法简单且利于量值传递。 相似文献
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Hirohisa Yokota Takahiro Hasegawa Yoshitaka Satoda Eiichi Sugai Yutaka Sasaki 《Optical Review》1999,6(3):173-179
Fused optical fiber grating couplers (FGCs), in which Bragg gratings are written in the coupling regions of fused optical fiber couplers with tapered shapes along them are theoretically and experimentally investigated. By coupled mode analysis considering these tapered shapes, the drop efficiencies of the FGCs, which are inherently zero for the normal fiber couplers without grating, are calculated. The grating offset, which is the difference between the centers of grating and the coupler taper, is found to be effective to increase the drop efficiency of the FGC. It is determined that the tapered shapes influence the wavelength dependence of the drop efficiency and tolerate the grating offset precision. Apodizations for the grating of FGC are found to be effective in suppressing side lobes of the drop efficiency. Measurement of the wavelength characteristics of drop efficiency and the temperature characteristics of drop wavelength of the fabricated fused FGC confirm that the lightwave with specific wavelength can be dropped by the FGC and that the temperature dependence of the drop wavelength is similar to that of Bragg wavelength changes of usual fiber Bragg gratings. 相似文献
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We have fabricated tapered photonic crystal fibers using a fusion splicer and experimentally observed the near-field mode distribution and the beam divergence of it. We have also compared characteristics of the tapered photonic crystal fiber with those of a tapered standard single-mode fiber. Unlike a tapered standard single-mode fiber, the mode field profile of a tapered photonic crystal fiber shows a good confinement of its field within the core region. The numerical apertures of tapered photonic crystal fibers are increased as the diameter of the fiber is decreased. 相似文献
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We have fabricated tapered photonic crystal fibers using a fusion splicer and experimentally observed the near-field mode distribution and the beam divergence of it. We have also compared characteristics of the tapered photonic crystal fiber with those of a tapered standard single-mode fiber. Unlike a tapered standard single-mode fiber, the mode field profile of a tapered photonic crystal fiber shows a good confinement of its field within the core region. The numerical apertures of tapered photonic crystal fibers are increased as the diameter of the fiber is decreased. 相似文献
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小芯径掺铒光纤与单模光纤低损耗接续的研究 总被引:1,自引:1,他引:0
报道了掺铒光纤放大器中降低掺铒光纤与单模光纤接续损耗的一种新方法,采用在芯区直径较小的掺铒光纤端部拉锥的方法,使得掺铒光纤中的传输模场在锥形区域内扩散,从而与单模光纤中直径较大的本征模场良好匹配,实现低损耗接续,初步实验结果表明,该方法可获得小于1dB的接续损耗。 相似文献
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Sbastien Guet RobbertV. Fortunati RobertF. Mudde Gijs Ooms 《Particle & Particle Systems Characterization》2003,20(3):219-230
The possibility to measure the velocity and size of individual bubbles in a high‐void fraction bubbly flow is investigated by using a four‐point optical fiber probe. The air bubbles have an initial spherical equivalent diameter ranging from 4 to 10 mm and the void fraction is up to 0.3. Firstly, single bubble experiments show that intrusiveness effects, i.e. bubble deformations due to the probe, are negligible provided that the bubble approaches the probe at the axis of the central fiber. A selection criterion is utilized for multiple bubble experiments. A good compromise can be found between the required accuracy, the duration of the measurements and the number of validated bubbles required for reliable statistical averaging. In an air‐water high‐void fraction vertical bubbly pipe flow, the void fraction obtained with the instrument is found to be in good agreement with both local single‐fiber probe measurements, and with the volume average void fraction obtained from pressure gradient measurements. The area average volumetric gas flow rate, based on the bubble velocity and void fraction as measured with the four‐point probe, agree with the measured gas flow rate. Also, the liquid velocity is measured by means of a laser‐Doppler anemometer, to investigate the slip velocity. The results show that reliable and interesting measurements can be obtained by using a four‐point optical fiber probe in high void fraction flows. 相似文献
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倒锥透镜型塑料光纤连接器光学特性研究 总被引:1,自引:0,他引:1
提出一种基于倒锥透镜光纤端的新型塑料光纤连接器.为了增大光纤的数值孔径,降低光纤端面对于对准准确度的要求,连接器的光纤连接端面制成倒锥透镜形状.利用截断法对该类型连接器的光学特性进行了测试.1 m长光纤跳线总损耗有75.7%集中在5.4 dB~6.0 dB之间,连接损耗70.7%集中在2.1 dB~2.7 dB之间,同一组跳线插拔200次连接损耗有95%集中分布在2.2 dB~2.58 dB.实验结果表明:倒锥透镜型塑料光纤连接器可以满足“光纤入户”对连接器性能的要求. 相似文献
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简要叙述光盘的结构原理、分类、光盘材料及其特性,并指出了材料的发展动向。对光纤的材料、塑料光纤的制备方法和特点以及发展方向与技术关键亦作了简要介绍。 相似文献