共查询到20条相似文献,搜索用时 15 毫秒
1.
Banmali Rawat Manoj Dalmia 《International Journal of Infrared and Millimeter Waves》1984,5(4):475-488
A computer aided design technique has been developed for the design of a beam splitter coupler and a distributed type coupler using inverted strip dielectric waveguides. The optical beam principle has been used for the beam splitter coupler. Numerical results for these couplers at 80 GHZ with minimum directivity of 30 dB and VSWR of 1.15 have been presented.This work was supported by the Faculty Research Committee of the University of North Dakota under research Grant Number 1813/0909/2369. 相似文献
2.
Alassane Sidibe Frédérique Gadot Benoit Belier Guillaume Bordier Davide Cammilleri Adnan Ghribi Andrea Tartari Michel Piat Joseph Martino François Pajot Faouzi Boussaha 《Applied Physics A: Materials Science & Processing》2014,117(2):523-526
Designed for astrophysical applications, this coupler must be as small as possible to be integrated in a low temperature superconducting detection chain. By using metamaterials, dimensions can be reduced and performances enhanced compared with a conventional coupler. The novelty of the work presented in this paper is a coupler that operates at millimeter waves (W band) and cryogenic temperatures (4 K) for astrophysics applications and more precisely for the detection of the cosmological microwave background radiation. 相似文献
3.
InP基1×4多模干涉耦合器的设计与制作 总被引:1,自引:0,他引:1
在密集波分复用系统中,多波长DFB激光器阵列与多模干涉耦合器集成光源器件具有重要的应用前景.为了研制多波长集成光源中的宽带可用低损耗光耦合器,利用三维有限差分光束传播法仿真设计了一种具有强限制作用的InP/InGaAsP材料的多模干涉型耦合器.输入/输出端波导均采用楔形结构以降低多模干涉型耦合器的插入损耗,提高各个输出端口的出光平衡度.根据仿真结果,结合波导芯层为采用外延生长设备,采用反应离子刻蚀工艺制作了1×乘4多模干涉型耦合器.利用自动对准波导耦合测试系统对所制作器件的插入损耗和出光平衡度进行测量.测试结果表明,该器件在1 550nm波长附近的40nm带宽范围内获得了约2.6dB的通带平坦度,在1 550nm通信波长处,器件的插入损耗低于10dB. 相似文献
4.
在密集波分复用系统中,多波长DFB激光器阵列与多模干涉耦合器集成光源器件具有重要的应用前景.为了研制多波长集成光源中的宽带可用低损耗光耦合器,利用三维有限差分光束传播法仿真设计了一种具有强限制作用的InP/InGaAsP材料的多模干涉型耦合器.输入/输出端波导均采用楔形结构以降低多模干涉型耦合器的插入损耗,提高各个输出端口的出光平衡度.根据仿真结果,结合波导芯层为采用外延生长设备,采用反应离子刻蚀工艺制作了1×乘4多模干涉型耦合器.利用自动对准波导耦合测试系统对所制作器件的插入损耗和出光平衡度进行测量.测试结果表明,该器件在1 550 nm波长附近的40 nm带宽范围内获得了约2.6 dB的通带平坦度,在1 550 nm通信波长处,器件的插入损耗低于10 dB. 相似文献
5.
A mode-selective directional coupler based on titanium in-diffused channel waveguides in lithium niobate is investigated.
This coupler may be utilized as a key part of an add-drop multiplexer for dense wavelength division multiplexing in optical
network nodes. The proposed coupler is based on evanescent coupling of the fundamental mode of a single-mode channel to the
first higher mode of a parallel bi-modal waveguide. Our experimental results show that a compact directional coupler with
coupling efficiencies larger than 90%, large bandwidth around 1550 nm, and with negligible polarization dependence can be
realized using electro-optic lithium niobate substrates.
Presented at 9-th International Workshop on Nonlinear Optics Applications, NOA 2007, May 17–20, 2007, Świnoujście, Poland 相似文献
6.
Mukesh Kumar Alaria A. K. Sinha A. Bera V. Srivastava 《International Journal of Infrared and Millimeter Waves》2008,29(12):1083-1090
The main objective of the paper is to make an efficient design of the input and output coaxial coupler for a helix TWTs. An
approach has been developed for the efficient design and analysis of the coaxial couplers in the practical situation. Normally
multi-section impedance transformer approach is used for any wide band coupler. For a space helix TWT, coupler should be wide
bandwidth and small size. In this case coupler is matched with helix slow wave structure and the standard 50-ohm connectors.
The simulated return loss (dB) profile for different type of couplers is obtained by using Ansoft HFSS, CST microwave studio
and compares those with experimental results. The tip loss design at sever ends for the input and the output section has been
also optimized. 相似文献
7.
Byung-Min Jung 《Optics Communications》2008,281(2):260-264
We propose a very short vertical directional coupler with polarization-insensitive high extinction ratios. The structure of the coupler has two deep-ridge waveguide structures in the upper and lower parts which can be implemented using a double-sided wafer process. The coupling length and extinction ratios of the vertical directional coupler with symmetric structures decrease as the thicknesses of the inner cladding layer and core layer decrease. The extinction ratio is improved using a slight asymmetry in the refractive indices of two core layers. As the thicknesses of the inner cladding layer and core layer decrease, the length of the vertical directional coupler for extinction ratios greater than 30 dB of both TE and TM modes decreases. A vertical directional coupler with a very short length less than 100 μm and polarization-insensitive high extinction ratios greater than 30 dB can be implemented using the structure proposed in this paper. 相似文献
8.
Self-Starting Passively Mode-Locking All-Solid-State Laser with GaAs Absorber Grown at Low Temperature 总被引:4,自引:0,他引:4
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We realize a stable self-starting passively mode-locking all-solid-state laser by using novel GaAs mirrors as the absorber and output coupler. The GaAs mirror is grown by the technology of metal organic chemical vapour deposition at low temperature. With such an absorber as the output coupler in the laser resonator, laser pulses with duration of 42ps were generated at a repetition rate of 400MHz, corresponding to the average power of 590mW. 相似文献
9.
10.
For the realization of optoelectronic integrated circuits, it is required to incident light perpendicularly to a planar Si photodiode. We propose a high-efficient vertical optical coupler using an amorphous Si optical waveguide grating coupler with top reflector, which is transparent at 850 nm wavelength range. The optical waveguide (width of 300 nm $\times $ height of 100 nm) coupler is analyzed by using finite element method. The coupling efficiency of 80 % is calculated at the grating period of 380 nm, the duty ratio of 0.75 and the depth of 35–65 nm with top metal reflector. 相似文献
11.
A pressure-sensitive device using an optical fiber coupler is proposed, and is integrated into an array system to measure sound field distributions. The optical coupling between two optical fibers is modulated by the applied sound field with the use of a membrane mechanically connected to the coupler. In the array system, a large number of the optical coupler sensors are connected two-dimensionally, and sound pressure at each sensor can be read out by switching the input light sources in turn. A prototype of the basic array system based on this principle was made, and its performance was demonstrated. The signal discrimination between each element was confirmed in a 2x2 array; then, using a four-element linear array, we demonstrated the steering of beam based on the phased array method. 相似文献
12.
The nonlinear switching characteristics of fused fiber directional couplers were studied experimentally. By using femtosecond laser pulses with pulse width of 100 fs and wavelength of about 1550 nm from a system of Ti:sapphire laser and optical parametric amplifier (OPA), the nonlinear switching properties of a null coupler and a 100% coupler were measured. The experimental results were coincident with the simulations based on nonlinear propagation equations in fiber by using super-mode theory. Nonlinear loss in fiber was also measured to get the injected power at the coupler. After deducting the nonlinear loss and input efficiency, the nonlinear switching critical peak powers for a 100% and a null fused couplers were calculated to be 9410 and 9440 W, respectively. The nonlinear loss parameter PN in an expression of αNL = αP/PN was obtained to be PN = 0.23 W. 相似文献
13.
Huijuan Zhang Chao Li Xiaoguang Tu Xianshu Luo Mingbin Yu Patrick Guo-Qiang Lo 《Applied Physics A: Materials Science & Processing》2014,115(1):79-82
In this paper, we have designed, fabricated and characterized silicon nitride grating couplers with high efficiency at 1490 nm. The devices are fabricated using deep UV photolithography with resolution requirement of ~500 nm. The grating coupler fabricated yields a peak coupling efficiency of ?5.1 dB. The 1-dB bandwidth of the grating coupler is 60 nm. 相似文献
14.
PAN Wei-Min HUANG Tong-Ming MA Qiang WANG Guang-Wei SUN Yi SHA Peng LI Zhong-Quan LIN Hai-Ying XU Bo 《中国物理C(英文版)》2008,32(9)
High power conditioning of the input coupler for BEPCⅡ supercOnducting cavity has been performed.After room temperature conditioning,the RF power of 150 kW with continuous wave at standing wave mode passed through the coupler without any problem.Meanwhile,a series of methods have also been studied to improve the performance of the coupler during the beam operation.Up to now,the input coupler can feed a RF power up to 100 kW stably with high current of 250 mA at 2.5 GeV. 相似文献
15.
High-power continuous-wave laser operation was demonstrated with a y-cut Yb:YCa(4)O(BO(3))(3) crystal, showing critical dependence on the output coupler used. Polarized laser oscillation with E||x was obtained at 1085.6 nm by using a coupler of 0.5% transmission, yielding an output power of 7.3 W with an optical-to-optical efficiency of 63%. Higher output couplings (>/=2%) led to polarized oscillation with E||z at laser wavelengths = 1055.5 nm, the highest output power was 6.5 W. Dual-wavelength operation in the two polarization states was realized with a coupler of 1% transmission, the output powers for the two orthogonal polarizations were 3.15 W at 1084.3 nm (E||x) and 3.45 W at 1061.3 nm (E||z). The slope efficiency for output couplers with transmission in the 0.5%-2% range was 81%-83%. 相似文献
16.
P.P. Sahu 《Optics Communications》2007,277(2):295-301
In this paper, a novel MMI coupler, based on general interference, with tapered waveguide geometry has been proposed for reduction of coupling length. The coupling characteristics and power imbalance of the proposed structure are compared with conventional MMI structures by using a mathematical model based on sinusoidal modes. It is seen that the beat length for tapered MMI coupler with angle of taper ∼1.05° is reduced by ∼24% of that of conventional MMI coupler and the coupling characteristics obtained with the mathematical model, match well with those obtained by more sophisticated BPM computer aided design software. The power imbalance for tapered 3 dB MMI coupler is more sensitive to the wavelength than that for conventional 3 dB MMI coupler and variation of power imbalance with fabrication tolerance for both the MMI coupler is almost same. 相似文献
17.
18.
An updated main coupler has been designed for the superconducting accelerator of Free Electron Laser (FEL) project under construction in Peking University. A capacitive structure is chosen for the main coupler. Numerical investigation using CST Microwave Studio demonstrates the cold window part. The other nonstandard structures such as holding rods and antenna are also optimized. The coupler uses a 95% purity Al2O3 ceramic cold window. The VSWR (Vottage Standing Wave Ratio) is 1.02 at 1.3 GHz and the frequency bandwidth is 45 MHz with VSWR<1.1. The electric field intensity is 8.5×10m-2 kV/mm around the window with 20 kW Continuous Wave (CW) transmitted power. The Qext is designed variable from 5×106 to 1×107. 相似文献
19.
利用变分法对腐蚀熔锥型非对称单模光纤耦合器的耦合特性进行了分析.文中根据耦合器的光纤参数及截面尺寸,用有效平行波导模型,对自制的弱融型熔锥耦合器的转换功率随波长变化曲线进行了计算.结果表明,不仅宽频带特性的理论曲线与实验符合得较好,而且耦合器的耦合特性对二光纤的芯径比及熔锥长度的变化十分灵敏,这也与实验相符. 相似文献
20.
Mamoru Kamikura Yu Tomimura Yutaro Sekimoto Shinichiro Asayama Wenlei Shan Naohisa Satou Yoshizou Iizuka Tetsuya Ito Toshiaki Kamba Yasutaka Serizawa Takashi Noguchi 《International Journal of Infrared and Millimeter Waves》2006,27(1):37-53
We have developed a 385–500 GHz sideband-separating (2SB) mixer, which is based on a waveguide split-block coupler at the
edge of the H-plane of the 508 μm × 254 μm (WR 2.0) waveguide, for the Atacama Large Millimeter/submillimeter Array (ALMA).
An RF/LO coupler, which contains an RF quadrature hybrid, two LO couplers, and an in-phase power divider, was designed with
the issue of mechanical tolerance taken into account. The RF/LO coupler was measured optically with a microscope and electrically
with a submillimeter vector network analyzer. The image rejection ratio (IRR) and the single-sideband (SSB) noise temperature
of the receiver using the RF/LO coupler have also been measured. The IRR was found to be larger than 8 dB and typically ∼
12 dB in the 385–500 GHz band. The SSB noise temperature of this receiver is 80 K at the band center, which corresponds to
4 times the quantum noise limit (hf/k) in SSB, and 250 K at the band edges.
An erratum to this article can be found at 相似文献