共查询到20条相似文献,搜索用时 9 毫秒
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光子晶体异质结耦合波导光开关 总被引:2,自引:0,他引:2
以二维三角晶格光子晶体为研究对象,在该光子晶体中引入两行平行的单模线缺陷波导,以一行耦合介质柱为间距,通过调节部分耦合介质柱的折射率,构筑了光子晶体异质结耦合波导光开关结构。利用平面波展开法和定向耦合原理计算了在不同入射光频率下,缺陷波导间耦合介质柱的折射率不同时的耦合长度,确定了合适的光子晶体异质结耦合波导光开关的结构参数。利用时域有限差分法研究了该光开关中耦合介质柱的折射率变化及异质结构介质柱的位置分布对光信号输出路径的影响。结果表明,通过改变该结构中耦合介质柱的折射率可以改变光的输出路径,可实现光的开关行为。并且异质结构介质柱位置的随机分布对该光开关的影响不大,有助于光子晶体新型滤波器、定向耦合器、波分复用器以及光开关等光子器件的研究。 相似文献
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L. Marazzi P. Parolari M. Brunero M. Martinelli P. Chanclou Q. Deniel 《Fiber and Integrated Optics》2014,33(3):173-183
AbstractNew applications are emerging in the optical access for wavelength-division multiplexed passive optical network colorless transmitters based on a reflective semiconductor optical amplifier. Previous works have shown that 10-Gb/s operation can be reached in the C-band with such transmitters, yet trade-offs are necessary for chromatic dispersion and, consequently, link length enters the equation. Such impairments are discussed using both experimental data and simulation results. New experimental data with interesting performance in the O-band are also presented. 相似文献
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Hideaki Okayama 《Optical Review》2001,8(4):294-300
The micro-machine scanner optical switch is gaining attention for its ability to switch over 100 ports. A beam steering error for devices using tilted mirrors or a moving lens is analyzed and schemes to overcome the limit are reported. The channel number is limited by the achievable beam steering error. A device with several hundred ports is possible with the beam steering error under 1#x0025;. Optimized focal length or fiber mode divergence angle is beneficial for increasing the channel number. To minimize the thermal expansion effect, large focal length is required indicating need for a compensation scheme to attain larger channel number. A new type of scanning optics is proposed to overcome the limit set by the beam steering error, and a new switch network described can further expand the channel number.This paper was originally presented at the 2nd International Conference on Optical Design and Fabrication, ODF2000 which was held on November 15-17, 2000 at the International Conference Center, Tokyo, Waseda University, Japan. 相似文献
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高效集成电光调制器和开关的电极与光波导的优化设计 总被引:2,自引:0,他引:2
集成电光调制与开关的效率取决于光波导中电光重叠因子Γ的大小,直接影响此因子的有电极宽度、电极间距、光模场尺寸、以及电极与光波导的相对位置等参量。本文利用集成电光调制器电极电场的分布规律,研究了各种结构中影响电光重叠因子的诸参量之间的关系;根据实际工艺条件,应用系统优化方法尽可能对各种参量进行优化计算,得到了实现高效调制和开关的全部参量的优化设计结果。 相似文献
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We present a scheme to realize two‐direction optical switch by a single‐mode optical cavity containing some four‐level atoms. The high switching efficiency can be obtained through low photon loss and large third‐order nonlinear susceptibility of this N‐type atomic system in cavity. Without the microwave source, it can be reduced to a Λ‐type atomic system where a coupling laser is used to realize single intracavity electromagnetically induced transparency (EIT). Namely, the probe field can be transmitted almost totally at resonance. Thus a two‐direction optical switch is operated and the state for forward (backward) direction is set as “open” (“closed”). When microwave source is introduced, dressed splitting of intracavity dark state happens. The probe field is reflected almost completely at resonance and the state of the optical switch at forward and backward directions (transmitted and reflected channels) is shifted as “closed” and “open”, respectively. Moreover, this scheme is much advantageous to realize splitting of intracavity dark state because weak microwave field () induces the coupling between intracavity dark state and one sublevel of ground state. While a strong pump laser () which couples the intracavity dark state with an excited level is applied to realize this splitting in ref. [Phys. Rev. A 85 013814 (2012)]. 相似文献
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大相对孔径紧凑型无热化红外光学系统设计 总被引:10,自引:3,他引:7
根据目前搜索和跟踪系统要求其红外成像光学系统具有高成像质量、超轻小型化和高温度适应性的特点。采用折反射式光学系统结构形式,基于J-T制冷型320×320凝视焦平面阵列探测器,设计了一种大相对孔径紧凑型无热化红外光学系统,光学系统远摄比达到0.6。采用光学被动消热差方法进行设计,使该系统在-40℃~60℃温度范围内实现了无热化。同时采用杂散辐射分析软件对系统进行杂散辐射分析,提出合理杂辐射抑制方案,给出了完整的光学系统设计。结果表明,光学系统在不同温度环境下所有视场的调制传递函数(MTF)(17lp/mm)均接近衍射极限,80%的能量集中在1个像元内,且具有结构紧凑、体积小等优点,可满足搜索和跟踪红外光学系统的使用要求。 相似文献
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A transparent optical network (TON) composed by optical add-drop multiplexers based on arrayed waveguide grating (AWG) with fabrication errors is optimized for 10 Gbit/s per channel and channel spacing of 25 GHz. The optimization takes into account the effect of inter-symbol interference, amplified spontaneous emission noise accumulation, and coherent and incoherent homodyne crosstalk. Numerical results reveal that AWG fabrication errors can have a high influence on the TON performance; however, in all investigated situations, they do not affect the AWG parameters values corresponding to the optimum AWG frequency response. This surprising behavior is due to the fabrication errors affect mainly the AWG response outside the passband for the required AWG crosstalk level. It is shown that the optimum AWG frequency response is a flat-top response with a mean amplitude response outside the passband lower than -30 dB and the switch isolation should exceed 30 dB. 相似文献
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A transparent optical network (TON) composed by optical add-drop multiplexers based on arrayed waveguide grating (AWG) with fabrication errors is optimized for 10 Gbit/s per channel and channel spacing of 25 GHz. The optimization takes into account the effect of inter-symbol interference, amplified spontaneous emission noise accumulation, and coherent and incoherent homodyne crosstalk. Numerical results reveal that AWG fabrication errors can have a high influence on the TON performance; however, in all investigated situations, they do not affect the AWG parameters values corresponding to the optimum AWG frequency response. This surprising behavior is due to the fabrication errors affect mainly the AWG response outside the passband for the required AWG crosstalk level. It is shown that the optimum AWG frequency response is a flat-top response with a mean amplitude response outside the passband lower than ?30 dB and the switch isolation should exceed 30 dB. 相似文献
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E. V. Barmina P. I. Rodin A. A. Serkov A. V. Simakin G. A. Shafeev 《Physics of Wave Phenomena》2018,26(2):99-108
It has experimentally been shown that the specular reflectance of some metals can be reduced by one to two orders of magnitude by subjecting them to multipulse laser ablation in air. An increase in the coefficient of grayness has been implemented for copper, nickel, aluminum, and stainless steel. Multipulse ablation of the corresponding targets leads to the formation of a quasi-periodic microstructure with an amplitude relief ranging from 30 to 50 μm. The specular reflectance of duralumin has been reduced using anodic oxidation of the microstructures formed by laser ablation and filling the newly formed pores with carbon nanoparticles. The thus obtained surfaces are close to ideal black body in their optical characteristics. 相似文献
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用传输矩阵法计算了两端对称缺陷复合光子晶体结构的光传输特性。计算结果表明:两端对称缺陷复合光子晶体[D(AB)mD]2结构中的禁带出现两个完全共振透射峰。通过控制入射光强来微调光子晶体材料的介电常数,使得完全共振透射峰移动,且介电常数变化越大,共振透射峰偏移越大,从而形成高效率的双通道光开关。当光子晶体为[D(AB)mD]N结构时,每个完全共振透射峰都分裂为N-1条,这样可通过调节N同时实现所需要通道数目的高效多通道光开关和多通道滤波器。 相似文献
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宽视场长焦距离轴三反射镜光学系统的设计 总被引:1,自引:0,他引:1
分析了离轴三反射镜系统成像特性.根据共轴三反射镜光学系统像差理论,确定结构参数的基本计算公式.设计了长焦宽视场的离轴三反射镜光学系统,分析了系统结构参量对像差的影响.结果表明,该系统视角较大,地面复益范围较宽,成像质量接近衍射极限. 相似文献