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Design of a compact polarization beam splitter based on a deformed photonic crystal directional coupler

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Chinese Physics B 2008年第7期17卷 2553-2556页

作者：任刚郑婉华王科杜晓宇邢名欣陈良惠 Nano-Optoelectronic Laboratory Institute of SemiconductorsChinese Academy of Sciences

In this paper a compact polarization beam splitter based on a deformed photonic crystal directional coupler is designed and simulated. The transverse-electric （TE） guided mode and transverse-magnetic （TM） guided mode are split due to different guiding mechanisms. The effect of the shape deformation of the air holes on the coupler is studied. It discovered that the coupling strength of the coupled waveguldes is strongly enhanced by introducing elliptical airholes, which reduce the device length to less than ***. A finite-difference tlme-domain simulation is performed to evaluate the performance of the device, and the extinction ratios for both TE and TM polarized light are higher than 20 dB.

关键词： photonic crystal polarization beam splitter directional coupler

Development of a 500-MHz waveguide directional coupler with high directivity for HEPS

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Radiation Detection Technology and Methods 2022年第3期6卷 323-329页

作者： Yuanli Luo Jian Li Pei Zhang Qiang Ma Haiying Lin Tongming Huang Fanbo Meng Facheng Zhao Ziwei Deng Institute of High Energy Physics(IHEP) Chinese Academy of Sciences(CAS)Beijing 100049China School of Nuclear Sciences and Technology University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Particle Acceleration Physics and Technology IHEPCASBeijing 100049China

Purpose In order to achieve a high-precision measurement of the incident and the reﬂected power,a WR1800 rectangular waveguide directional coupler with high directivity and high power level has been in-house *** couplers will be installed in the 500-MHz high-power radio-frequency transmission lines delivering 200-kW continuous-wave power for the High Energy Photon Source(HEPS).Methods The directional coupler adopts the design scheme of primary and secondary transmission lines and coaxial coupling-head *** shape and dimensional parameters of the coupling head were carefully optimized by using microwave simulation *** optimum directivity of 64 dB was achieved in *** and conclusions A prototype coupler was subsequently manufactured,and its directivity was measured to be 48.2 dB following a rigorous calibration procedure,largely exceeding the design goal and the commercial *** coupler was then connected to an existing 500-MHz klystron system,and a high-power test with short-circuit termination was *** high directivity of the coupler was conﬁrmed up to 200 *** the 6 hours of power aging with continuous-wave 200 kW in a standing-wave setup,no performance degradation was observed on the *** coupler temperature was measured to be 20◦C above the ambient *** design requirements were comfortably fulﬁ*** constitute theﬁrst in-house development of a large-size waveguide directional coupler with high directivity and high power level for *** design,fabrication,and performance tests of the directional coupler are presented.

关键词： directional coupler High directivity Simulation optimization High-power RF High Energy Photon Source

RF design and test of a high-directivity high-power waveguide directional coupler for the HEPS

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Radiation Detection Technology and Methods 2022年第2期6卷 137-142页

作者： Xiang He Jing-Ru Zhang Jing-Dong Liu Hua Shi Bing-Lin Deng Xu-Jian Wang Sheng-Chang Wang Nan Gan Pi-Long Tian Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

Purpose A novel high-directivity high-power waveguide directional coupler(DC)working at 2998.8 MHz is developed for the High Energy Photon *** can help the phase control system to obtain a very accurate microwave signal,which is very important to minimize the beam *** The novel reversely placed T-type coupling piece helps to obtain a high *** N-type high-vacuum feedthroughs for vacuum sealing instead of the traditional ceramic plate is beneficial to holding a higher peak *** simulation and the high-power commissioning are accomplished in the Institute of High Energy Physics(IHEP),while the fabrication and the low-power test are conducted in cooperation with the *** Both the single-coupler and the dual-coupler DCs are developed with a directivity of more than 35 dB while keeping the coupling factor within 60±0.5 ***,69.4%of all the fifty-two mass produced DCs have got a directivity of more than 40 ***:The mature manufacturing process for mass production is *** novel high-directivity high-power waveguide DC can be mass produced with an actually internationally leading performance.

关键词： HEPS directional coupler High directivity High power Mass production

Nonideal effects in quantum field-effect directional coupler

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Chinese Physics B 2006年第10期15卷 2415-2421页

作者：谢月娥颜晓红陈元平 Institute of Modern Physics and Department of Physics Xiangtan University Xiangtan 411105 China College of Science Nanfing University of Aeronautics and Astronautics Nanjing 210016 China

The nonideal effects in a quantum field-effect directional coupler where two quantum wires are coupled through a finite potential barrier are studied by adopting the lattice Green function method. The results show that the electron energy distribution, asymmetric geometry and finite temperature all have obvious influence on the electron transfer of the coupler. Only for the electrons with energies in a certain region, can the complete periodic transfer between two quantum wires take place. The conductance of these electrons as a function of the barrier length and potential height exhibits a fine periodic or quasi-periodic pattern. For the electrons with energies beyond the region, however, the complete periodic transfer does not hold any more since many irregular oscillations are superimposed on the conductance profile. In addition, the finite temperature and asymmetric geometry both can reduce the electron transfer efficiency.

关键词： nonideal effects directional coupler Green function

Silicon-based on-chip diplexing/triplexing technologies and devices

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Science China(Information Sciences) 2018年第8期61卷 18-32页

作者： Yaocheng SHI Jingye CHEN Hongnan XU Centre for Optical and Electromagnetic Research State Key Laboratory of Modern Optical InstrumentationZhejiang University

Wavelength-division-multiplexing(WDM) transceiver filters are one of the most essential components for realizing the fiber-to-the-home(FTTH) networks. In recent years, silicon photonics have provided a very attractive platform to build ultra-compact photonic integrated devices with CMOS-compatible processes. In this review, we focus on the recent progresses on diplexers/triplexers based on multimode interference couplers(MMI), and directional couplers(DC). The polarization-insensitive devices are also discussed.

关键词： wavelength division multiplexer multimode interference coupler directional coupler fiber-tothe-home silicon waveguide

A design method for high fabrication tolerance integrated optical mode multiplexer

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Science China(Information Sciences) 2020年第6期63卷 184-194页

作者： Bitao SHEN Haowen SHU Linjie ZHOU Xingjun WANG State Key Laboratory on Advanced Optical Communication Systems and Networks Department of ElectronicsSchool of Electronics Engineering and Computer Science Peking University State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Nano-optoelectronics Frontier Center of Ministry of Education Peking University

The tapered asymmetric directional coupler has the potential to realize high fabrication tolerance and high transmission efficiency on-chip mode multiplexer. However, the geometry parameter selection of tapered structure remains empirical. In this paper, we propose a design method for the tapered structure based on genetic algorithm. Combined with the adjusted coupling equations and interpolation method, lowtime-cost optimization can be realized. Three mode multiplexers(TE0&TE1, TE0&TE2 and TE0&TE5)are designed by our method. According to simulation results, the insertion loss of the designed devices is lower than 1.8 dB and the crosstalk is lower than-15 dB when the fabrication error is within required range(±10 nm for TE0&TE2 and TE0&TE5, and ±20 nm for TE0&TE1) in the bandwidth of 1.5–1.6 μm. In addition, the entire optimization process takes only 2 h for each device, which is around the time cost of a single 3 D simulation.

关键词： mode multiplexer directional coupler taper structure coupled-mode theory genetic algorithm

Duplexer Design for Full-Duplex Based Wireless Communications

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China Communications 2016年第11期13卷 1-13页

作者： Hui Zhuang Jintao Li Weibiao Geng Xiaoming Dai Beijing Engineering and Technology Research Center for Convergence Networks and Ubiquitous Services School of Computer and Communication EngineeringUniversity of Science and Technology

The full-duplex(FD) based wireless communication devices,which are capable of concurrently transmitting and receiving signals with a single frequency band,suffer from a severe self-interference(SI) due to the large power difference between the devices' own transmission and the useful signal comes from the remote transmitters. To enable the practical FD devices to be implementable,the SI power must be sufficiently suppressed to the level of background noise power,making the received signal-to-interference-plus-noise ratio(SINR) satisfy the decoding requirement. In this paper,the design and implementation of the duplexer for facilitating SI cancellation in FD based wireless communications are investigated,with a new type of duplexer(i.e. an improved directional coupler) designed for improving the spatial suppression of the SI power. Furthermore,the practical circuit boards are designed and verified for the proposed prototype,showing that the spatial suppression capability may be up to 36 d B(i.e. much higher than that attainable in the commonly designed ferrite circulator) by using the proposed design.

关键词： full-duplex wireless communications Self-interference cancellation Duplexer directional coupler

The Coupled-mode Theory of Grating-assisted Parallel Optical Fiber Cores

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Chinese Journal of Lasers 2002年第1期11卷 52-57页

作者： ZHU Songlin ZHANG Xianmin CHEN Kangsheng (Department of Information & Electronic Engineering, Zhejiang University, Hangzhou 310027, China) Department of Information & Electronic Engineering Zhejiaiig University Hangzhou 310027

A new coupled-mode formulation is developed for grating-assisted parallel optical fiber cores. The theory is derived from the scalar wave equation by perturbation method. The diffraction caused by grating and coupler in the grating region are both considered. Based on the theory, various experimental phenomena in grating-assisted parallel optical fiber cores can be simulated accurately.

关键词： fiber grating coupled-mode directional coupler

An Ultra-Compact Broadband Polarizing Beam Splitter Utilizing Hybrid Plasmonic Waveguide

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China Communications 2023年第6期20卷 49-59页

作者： Li Zhang Jiaqi Liu Can Pan Yatao Yang College of Electronics and Information Engineering Shenzhen UniversityShenzhen 518000China

Polarizing beam splitter has rather significant applications in polarization diversity circuits and polarization multiplexing *** this paper,we present an asymmetric polarizing beam splitter utilizing hybrid plasmonic *** special hybrid structure with a hybrid waveguide and a dielectric waveguide can limit the energy of TE and TM modes to a different ***,we can achieve beam splitting by adjusting the corresponding parameters of the two ***,we studied the influences of different structure parameters on the real part of the effective mode refractive index of the two waveguides,and obtained a set of parameters that satisfy the condition of strong coupling of TM mode and weak coupling of TE ***,the performance of our proposed polarizing beam splitter is evaluated *** length of the coupling section is only 4.1μm,and the propagation loss of TM and TE modes is 0.0025 d B/μm and 0.0031 d B/μm ***,the extinction ratios of TM and TE modes are 10.62 d B and 12.55 d B,***,the proposed device has excellent wavelength *** the entire C-band,the fluctuation of the whole normalized output power is less than *** short,our proposed asymmetric polarizing beam splitter features ultra-compactness,low propagation loss,and broad bandwidth,which would provide promising applications in polarization multiplexing system and polarization diversity circuits relevant to optical interconnection.

关键词： polarizing beam splitter hybrid plasmonic waveguide directional coupler polarization multiplexing systems