• Title, Summary, Keyword: Directional couplers

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Measurement and Analysis of Loss in Optical Directional Couplers

  • Leepila, R.;Jangsilp, R.;Noppanakeepong, S.
    • 제어로봇시스템학회:학술대회논문집
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    • pp.484-487
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    • 2004
  • Symmetric directional couplers are widely used in interferometers, switches, and various signal processing devices. Recently, several optical couplers using multimode fibers were reported, but these suffer from inefficient coupling of light into a branching fiber and/or low directivity. This paper presents the measurement and analysis of loss in the connection of optical fibers via the optical directional couplers. The functionality of the device is based on the principle that is symmetrical, the power in excited mode can be unambiguously directed into one of the output channel by varying and of its parameters. In this experiment, we measure the power of loss in the optical directional coupler at various radius of curvature. Before the measurement of loss in x-coupler, we polish the contact of the fiber surface in order that light can penetrate through another port. The results show that, when the radius of curvature is increased, the loss power is decreased and also approaches of the straight line case.

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Application of the Beam Propagation Method to the analysis of Dual-channel directional couplers (Dual-channel directional couplers 동작특성 해석을 위한 BPM의 적용)

  • Kang, Kyung-Woo;Kang, Hyung-Boo
    • Proceedings of the KIEE Conference
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    • pp.660-662
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    • 1993
  • We have numerically analyzed by using the Beam Propagation Method the Dual-channel directional couplers, which peforms a number of useful fuctions in thin-films devices, including power division, modulation, switching, frequency selection, and polarization selection. We also use the effective index method to reduce one dimension.

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Design and Characterization of 3 dB Branch Type Directional Couplers using High-Tc Superconductors (고온초전도체를 이용한 가지 형태 3 dB 방향성 결합기 설계 및 특성해석)

  • Chung, Dong-Chul;Choi, Myoung-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.116-119
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    • 2010
  • In this work, we presented the characterization of 3 dB branch type directional couplers by using High-Tc superconducting thin films. To do this, we deposited YBCO superconducting thin films on MgO substrates by using rf-magnetron sputtering techniques. The designed center frequency was 408 MHz and the designed passband was 20 MHz. Also we designed 3 dB Power difference and $90^{\circ}$ of phase difference between port 3 and port 4. The even and odd mode analysis were used to characterize our directional couplers and em Sonnet (full wave analysis program) was utilized to the optimum design. We reported experimental results, including a center frequency, passband, half power characteristics and phase differences. We confirmed that experimental results were in good agreements with characterization by using full wave analysis program.

Embedded RF Test Circuits: RF Power Detectors, RF Power Control Circuits, Directional Couplers, and 77-GHz Six-Port Reflectometer

  • Eisenstadt, William R.;Hur, Byul
    • Journal of information and communication convergence engineering
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    • v.11 no.1
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    • pp.56-61
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    • 2013
  • Modern integrated circuits (ICs) are becoming an integrated parts of analog, digital, and radio frequency (RF) circuits. Testing these RF circuits on a chip is an important task, not only for fabrication quality control but also for tuning RF circuit elements to fit multi-standard wireless systems. In this paper, RF test circuits suitable for embedded testing are introduced: RF power detectors, power control circuits, directional couplers, and six-port reflectometers. Various types of embedded RF power detectors are reviewed. The conventional approach and our approach for the RF power control circuits are compared. Also, embedded tunable active directional couplers are presented. Then, six-port reflectometers for embedded RF testing are introduced including a 77-GHz six-port reflectometer circuit in a 130 nm process. This circuit demonstrates successful calibrated reflection coefficient simulation results for 37 well distributed samples in a Smith chart. The details including the theory, calibration, circuit design techniques, and simulations of the 77-GHz six-port reflectometer are presented in this paper.

Design of X band Microstrip Directional Couplers (X-대역 마이크로 스트? 방향성 결합기의 설계)

  • 양인응;홍완희
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.12 no.4
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    • pp.7-14
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    • 1975
  • A significant new technique in the dsvelopment of micro-wave circuits is the process of untilization of coupled lines in the transverse electro-magnetic field. The bases for this technique are the application of even-and odd-mode characteristic impedances of the transmission line. This article describes the properties of directional couplers and explains a prccfdure usrd to design micro-strip directional couplers with the aid of the computer. The article also describes the experimental results obtained from seven microstrip couplers, which were built to verify the computer program and the approximate solutions. It can be seen that in cases at X-band where couplings of 10 to 20dB are required, the computer program and approximate solutions will produce good results.

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Novel Lumped Element Backward Directional Couplers Based on the Parallel Coupled-Line Theory (평행 결합선로 이론에 근거한 새로운 집중 소자형 방향성 결합기)

  • 박준석;송택영
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.10
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    • pp.1036-1043
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    • 2003
  • In this paper, novel lumped equivalent circuits for a conventional parallel directional coupler are proposed. This novel equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of a parallel-coupled line. By using the derived design formula, we have designed the 3 dB and 10 dB lumped element directional couplers at the center frequency of 100 MHz and 2 GHz, respectively a chip type directional coupler has been designed with multilayer configurations by employing commercial EM simulator. Designed chip-type directional couplers have a 3 dB-coupling value at the center frequency of 2 GHz and fabricated lumped directional coupler on fr4 organic substrate has a 3 dB, 10 dB-coupling values at the center frequency of 100 MHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper. Furthermore, in order to adapt to multi-layer process such as Low Temperature Cofired Ceramic (LTCC), chip-type lumped element couplers have been designed by using this method.

Coupled Trigonomotric Transmission Line and its Application (결합삼각함수 선로와 그 응용)

  • 박송배
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.12 no.6
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    • pp.14-20
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    • 1975
  • Characteristics of coupled trigonometric transmission lines (CTTL) are studies based on the theory of general coupled nonuniform transmission lines. First, the 4-port transmission matrix parameters of networks and directional couplers using CTTL. The phase slrift characteristic of the all-pass networks and the magnitude characteristic of the directional couplers are studied in detail for various coupling and a high-pass small ripple directional coupler using CTTL are given and their physical realization is considered.

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A Novel Transversal Filter using Triple-Coupled-Line Directional Couplers (삼중 결합선로 방향성결합기를 이용한 새로운 구조의 트랜스버살 필터)

  • 지기만;박동철
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.6
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    • pp.591-598
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    • 2003
  • A novel transversal filter using triple-coupled-line directional couplers is proposed. Simple design method which uses sinc function for computing coupling coefficients of the proposed transversal filter are also introduced. The frequency characteristics of the proposed filter are seldom degraded by the connecting sections between the cascaded directional couplers while those of the conventional transversal filter are aggravated. Moreover, the less number of the connecting sections and the directional couplers is required in the proposed filter than fer the case of the conventional transversal filter having the same bandwidth. The performance of the proposed transversal filter is verified by measurement and the measured results are compared with the calculated results.

Fabrication and Characteristics of Plastic Optical Fiber Directional Couplers

  • Kim Dae-Geun;Woo Sae Yoon;Kim Dong-Kwan;Park Seung-Han;Hwang Jin-Taek
    • Journal of the Optical Society of Korea
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    • v.9 no.3
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    • pp.99-102
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    • 2005
  • Directional couplers of gradient-index plastic optical fibers were fabricated and characterized. In particular, we have employed a core-facet technique to make the directional couplers, which require mechanical side polishing and linkage. We have measured insertion loss, excess loss, and coupling ratio of the fabricated couplers as a function of polishing depth and coupling length. We found that polishing depth of $\~300{\mu}m$ and coupling length of $\~35mm$ are optimum conditions for minimizing the insertion and excess losses and for achieving 1: 1 coupling ratio.

Design of optical directional couplers using Nano-Scale MQWs (나노 양자우물구조를 이용한 광통신용 방향성 결합기의 설계)

  • Ho, Kwang-Chun
    • Korean Journal of Optics and Photonics
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    • v.16 no.2
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    • pp.162-167
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    • 2005
  • An optical directional coupler, which consists of quantum wells with nanothickness, is designed by using Modal Transmission Line Theory (MTLT). To demonstrate the validity and usefulness, the propagation characteristics and the coupling efficiencies are rigorously evaluated at nanoscale couplers, which consist of double quantum wells with different effective masses. The numerical result reveals that the coupling efficiency of nanoscale couplers is maximized at a coupling length 2052.3 nm, if the total electron energy is 83.9 meV. Furthermore, the coupler operates as a filter with narrower band as the barrier thickness increases.