共查询到20条相似文献,搜索用时 15 毫秒
1.
C Alonso-Ramos R Halir A Ortega-Moñux P Cheben L Vivien I Molina-Fernández D Marris-Morini S Janz DX Xu J Schmid 《Optics letters》2012,37(17):3534-3536
Integrated polarization rotators are known to exhibit stringent fabrication tolerances, which severely handicap their practical application. Here we present a general polarization rotator scheme that enables both the compensation of fabrication errors and wavelength tunability. The scheme is described analytically, and a condition for perfect polarization conversion is established. Simulations of a silicon-on-insulator polarization rotator show polarization extinction ratios in excess of 40 dB even in the presence of large fabrication errors that in a conventional rotator configuration degrade the extinction ratio to below 5 dB. Additionally, wavelength tuning over ±30 nm is shown. 相似文献
2.
Frequency-selective microwave polarization rotator using substrate-integrated waveguide cavities
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A frequency selective polarization rotator that can rotate the polarization angle of an incident electromagnetic wave at the microwave frequency by 45 is presented. The polarization rotator is based on a two-dimensional periodic array of substrate integrated waveguide cavities, realizing the polarization rotation by coupling the input signal to the output wave through three metallic slots. Two layers of frequency selective surfaces are cascaded by substrate and form the polarization rotator. A vertical slot on the top layer is used to select the horizontal polarization from the incident wave, the vertical and the horizontal slots on the bottom layer are, respectively, used to obtain horizontally and vertically polarized outgoing waves. The two orthogonal outgoing waves are combined to result in the 45~ polarized wave. Both full wave simulation and experimental measurement are carried out, together validating the proposed method. 相似文献
3.
H. C. Meyer G. A. Tanton S. S. Mitra J. D. Stettler 《Applied Physics A: Materials Science & Processing》1977,13(3):307-309
The Faraday rotation associated with the Zeeman effect in gases is used to rotate the plane or polarization of plane polarized
light with low loss of intensity. Advantage is taken of the rapid decrease of absorption relative to Faraday rotation between
the split Zeeman components. Calculations of this Faraday rotation are applied to obtain design parameters for an isolator
for 5.26 μm which show a significant improvement over conventional designs. 相似文献
4.
We present a design of a linear optical waveguide that utilizes a C-shaped metallic nano-aperture that efficiently transports light while maintaining a spot size of lambda/10. The performance of a C-aperture waveguide is superior to both a regular ridge waveguide and other surface plasmon based metal nano-optical waveguides. The energy transport mechanisms are explained by the coupling of an aperture surface resonance and the thickness resonances inside the guide channel. Finite-difference time-domain simulations of gold C-aperture waveguides are performed for a 1.5 microm wavelength incident plane wave. The 1/e decay length in power transmission is predicted to be approximately 2.5 microm. The total power throughput is 1.66 for the 2.55 microm long guide, with an intensity 6 times that of the incident wave at a distance 120 nm from the exit plane, having a spot size of 150 nm. 相似文献
5.
We demonstrate a low-loss terahertz waveguide based on the InAs-graphene-SiC structure. By analyzing the terahertz waveguide proposed in this paper, we can obtain that it is the characteristic of a low transmission loss coefficient(αloss≈0.55 dB/m) for fundamental mode(LP01) when the incident frequency is larger than 3.0 THz. The critical radii of the inside and outside cylinders have been found for the high-quality transmission. The large inside radius and the high transmission frequency result in a flat transmission loss coefficient curve. As a strictly two-dimensional material, the double graphene surface rings perform better to improve the quality of transmission mode. These results provide a new idea for the research of the long-distance THz waveguide. 相似文献
6.
《Infrared physics》1978,18(5-6):741-747
Groove guide is potentially attractive as a low-loss low-mode guide for the 100–1000 GHz frequency range. The theoretical characteristics, including the ability to reject higher order modes, are discussed. Experimental measurements of performance at 100 and 890 GHz are presented. 相似文献
7.
C. Prigent P. Abba M. Cheudin 《International Journal of Infrared and Millimeter Waves》1988,9(5):477-490
We present the theory and first measurements concerning a quasi-optical polarization rotator capable of operating over a broad frequency band.It consists of a wire-grid polarizer and a plane mirror with quarter-wave spacing. It permits a single fixed receiver to analyse alternatively two orthogonal components of a signal. Its ease of realisation and use makes it appear as an attractive device in the millimeter and submillimeter region. 相似文献
8.
We present a highly efficient integratable waveguide transformer that is capable of converting Gaussian-like waveguide modes to much more complicated non-Gaussian-like slot-waveguide modes, and vice versa. The structure consists of several pairs of complementary tapers capable of making this mode conversion virtually lossless. The capability of extremely low-loss mode transformation between these two classes of waveguides has been demonstrated by means of single- and double-slot transformers. Our simulation has shown that the total transformation losses are less than 0.01 and 0.02 dB per transformer, respectively, and can be easily achieved, with a total device length of less than 100 microm. 相似文献
9.
To achieve low loss and complete confinement of light, we propose and study a plasmonic hybrid optical waveguide fabricated on an silicon-on-insulator substrate. Using controlled oxidation and etching processes, a deep submicrometer Si core is fabricated based on UV photolithography patterning. The as-fabricated waveguide demonstrates a very low propagation loss of 1.6 dB/mm at 1550 nm. The numerical study discloses the hybrid characteristics of the mode. It is shown that the optical power of the waveguiding mode distributes more in the high-index Si-core region, and the metal cover further confines the light beyond the diffraction limit. The hybrid waveguide may be applied in compact, high-density Si photonic integrated circuits. 相似文献
10.
扇形波导可作为高功率微波圆柱共形波导缝隙阵天线的基本单元。分析了扇形波导中主模场分量,根据实际情况对主模场进行了合理近似。采用互易定理推导由波导主模横向场分量和缝隙场分量表示的波导场分量的前向或后向散射系数。根据波导传输线理论,将波导宽边纵缝等效为并联导纳,再根据波导边界条件得到扇形波导宽边谐振纵缝的归一化电导与波导散射系数之间的关系式。根据缝隙天线与振子天线的互补关系得到扇形波导谐振缝隙的辐射阻抗,结合波导功率平衡关系得到由波导横向场散射系数表示的缝隙辐射功率表达式,得到归一化电导的与谐振宽边纵缝的偏移位置、缝隙宽度、波导波长以及扇形波导尺寸参数之间的解析表达式。给出了算例,在波导中间区域,通过商用软件计算得到的电导与理论公式结果基本吻合。 相似文献
11.
Alonso-Ramos C Romero-García S Ortega-Moñux A Molina-Fernández I Zhang R Bach HG Schell M 《Optics letters》2012,37(3):335-337
A polarization rotator, suitable for integration in a polarization diversity optical receiver fabricated in InP technology, is proposed. The device, based on a two steps waveguide rotator, includes tapered input and output ports that provide very low insertion loss (<0.04 dB). An extinction ratio of 40 dB at 1550 nm wavelength is calculated, comparable or even superior to other state of the art polarization converters. The main advantage of the proposed design is the capability of implementation using a standard fabrication process with only two dry etch steps, significantly reducing complexity and cost. 相似文献
12.
M. V. Davidovich 《Technical Physics》2006,51(11):1405-1413
Integral immitance equations for steady-state excitation of a shielded waveguide transformer with any number of arbitrarily arranged adjoint semi-infinite waveguides are derived in the general formulation. Excitation can be carried by arbitrary inner sources (extraneous electric and magnetic currents), as well as by normal modes incident from infinity. The results are extended to the case of nonideal walls for magnetodielectric and metallic inclusions. The results give a generalization of the familiar integral impedance and admittance equations for inhomogeneous waveguides. 相似文献
13.
扇形波导可作为高功率微波圆柱共形波导缝隙阵天线的基本单元。分析了扇形波导中主模场分量,根据实际情况对主模场进行了合理近似。采用互易定理推导由波导主模横向场分量和缝隙场分量表示的波导场分量的前向或后向散射系数。根据波导传输线理论,将波导宽边纵缝等效为并联导纳,再根据波导边界条件得到扇形波导宽边谐振纵缝的归一化电导与波导散射系数之间的关系式。根据缝隙天线与振子天线的互补关系得到扇形波导谐振缝隙的辐射阻抗,结合波导功率平衡关系得到由波导横向场散射系数表示的缝隙辐射功率表达式,得到归一化电导的与谐振宽边纵缝的偏移位置、缝隙宽度、波导波长以及扇形波导尺寸参数之间的解析表达式。给出了算例,在波导中间区域,通过商用软件计算得到的电导与理论公式结果基本吻合。 相似文献
14.
Jing Xiao Jiansheng Liu Zheng Zheng Yusheng Bian Guanjun Wang Shuna Li 《Optics Communications》2012,285(17):3604-3607
In this paper, a novel metal-insulator-semiconductor waveguide with an air core in the insulator layer is proposed in order to improve the on-chip integration. Compared with the structure with homogeneous insulator, the introduced air core provides an additional degree of freedom for tuning the characteristics of the hybrid plasmonic mode. Simulation results demonstrate that the proposed structure exhibits better tradeoff between the mode confinement and the propagation length. The relatively low crosstalk between adjacent proposed waveguides could be achieved and the coupling efficiency between conventional silicon waveguide and the proposed structure maintain. The proposed waveguide could be used to build ultra-compact photonic components and enable on-chip integration of photonic circuits. 相似文献
15.
16.
Vincent K.S. Hsiao Wei-Huan Fu Ching-Yun Huang Zhe Chen Siben Li Jianhui Yu Jun Zhang Jieyuan Tang 《Optics Communications》2012,285(6):1155-1158
This study demonstrates an all-fiber optical polarization rotator and switch based on a side-polished fiber (SPF) overlaid with a photoresponsive liquid crystal (LC) containing a nematic LC and a photosensitive azobenzene molecule. The trans-cis photoisomerization of azobenzene modulates the overlaid LC's birefringence, changes the refractive index (RI) of the photoresponsive LC-overlaid SPF, and further controls and switches the phase retardation. This design achieves a 10° phase shift under switching time of less than 1 s. The demonstration has potential for an optically tunable in-line 2 × 2 fiber-optic switch or microstructured fiber-based photonic device controlled by the polarization of light. 相似文献
17.
We present a procedure to generate wideband and low dispersion slow light in slotted photonic crystal waveguide. By shifting the first and second rows of air holes of slotted photonic crystal waveguide, the bandwidth of slow light can be increased, with small group velocity dispersion. Using 2D plane wave expansion method, we numerically demonstrate slow light with the nearly constant group indices of 23, 42, and 54 over 17.6 nm, 6.7 nm and 3.3 nm bandwidth, respectively. The maximal normalized delay-bandwidth product is 0.26. From the fabrication's point of review, shifting the position of holes is easier to be controlled technically than changing the diameters of air holes. In addition, our simulations suggest this design is tolerant to deviation for positions of the first two rows of air holes. Therefore, the proposed approach decreases the dependence on the fabrication accuracy. 相似文献
18.
根据Stevenson等效电路法设计了两个X波段低副瓣波导缝隙阵列天线。通过建立多个缝隙时的谐振长度提取模型,计算了存在缝隙间互耦时的谐振长度。两个阵列天线测试结果和仿真结果吻合良好,线阵中心频率实测增益为17.83dB,其仿真结果为18.2dB,实测副瓣为-28.12dB,其仿真结果为-29.97dB;平面阵列中心频率实测增益为27dB,其仿真结果为27.9dB,实测H面副瓣为-27.2dB,其仿真结果为-29.9dB,实测E面副瓣为-22dB,其仿真结果为-22dB。 相似文献
19.
:根据Stevenson等效电路法设计了两个X波段低副瓣波导缝隙阵列天线。通过建立多个缝隙时的谐振长度提取模型,计算了存在缝隙间互耦时的谐振长度。两个阵列天线测试结果和仿真结果吻合良好,线阵中心频率实测增益为17.83 dB,其仿真结果为18.2 dB,实测副瓣为-28.12 dB,其仿真结果为-29.97 dB;平面阵列中心频率实测增益为27 dB,其仿真结果为27.9 dB, 实测H面副瓣为-27.2 dB,其仿真结果为-29.9 dB,实测E面副瓣为-22 dB,其仿真结果为-22 dB。 相似文献