• Title/Summary/Keyword: and multimode interference coupler

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Design of optical power splitters and couplers composed of deeply etched multimode interference section (깊이 식각된 다중모드 간섭 영역으로 구성된 광전력 분배기 및 결합기의 설계)

  • 김정욱;정영철
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.4
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    • pp.62-72
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    • 1997
  • The optical power splitter/couplers based on MMI(multimode interference) in GaAs/AlGaAs are studied. We presetn a design of optical power splitter/couplers, which have deeply etched multimode waveguide. The properties and fabrication tolerance on the etching depth, multimode waveguide width are simulatedusing a FD-BPM (finite difference beam propgation method). Proposed 1*N optical of designed device is 0.7dB smaller than the optical power splitter with a shallowly etched MMI section. For 0.5dB excess loss, the predicted fabrication tolerance is 0.6.mu.m on the multimode waveguide width of the 14 optical power splitter with a deeply etched MMI section. Also excess loss and uniformity of poposed 32*32 optical power coupler are below 0.3dB. The excess loss of proposed 32*32 optical power coupler is 2dB smaller than the optical power coupler with a shallowly etched MMI section. It is shown that the optical power splitters/couplers with a deeply etched mMI section have low loss, good uniformity, and improved fabriction tolerance.

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Design of Optical Multimode Interference Couplers with Ultracompact Propagating Width (초소형 전송폭을 갖는 광 다중모드 간섭결합기의 설계)

  • Ho, Kwang-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.1
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    • pp.47-52
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    • 2011
  • In this paper, to evaluate the design properties of 3D optical multimode interference (MMI) couplers with ultracompact width, modal transmission line theory and effective dielectric method are combined with together. A coupling efficiency based on the composed approach is defined, and the coupling length is numerically determined for the design of 3 dB coupler, cross coupler and bar coupler. The simulation result shows that the designed MMI coupler has a low insertion loss and a high splitting ratio.

Design of Polarization-Insensitive Directional Couplers and Multimode Interference Couplers Integrated with Bragg Grating Waveguide (Bragg 격자구조가 집적된 편광 무의존성 방향성 결합기와 다중모드 간섭 결합기의 설계)

  • Ho, Kwang-Chun
    • Korean Journal of Optics and Photonics
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    • v.18 no.5
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    • pp.295-302
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    • 2007
  • This paper presents a rigorous comparison of the design characteristics of polarization-insensitive directional coupler (DC) and multimode interference (MMI) coupler based on rib type waveguides, by using longitudinal modal transmission-line theory (L-MTLT). It shows that the multimode mixing and interference property of MMI can be structurally designed through the continuous evolution of the two-mode coupling property of DC. It also compares and analyzes the coupling efficiency along with the coupling length and the wavelength between polarization-insensitive DC and MMI. From the design properties obtained, it demonstrates for the first time the integration of polarization-insensitive DC or MMI with a Bragg grating and evaluates precisely the filtering characteristics. The numerical results reveal that the DC, as long as it is designed to have the same coupling length for TE and TM modes, has better performance than the MMI in polarization-insensitive filtering behaviour. However, it shows that the MMI with much less coupling length than DC is preferred in the miniaturization of integrated devices.

Triangular Ring Resonator Without Direct Coupling Between Two Access Waveguides of Multimode Interference Coupler (다중모드 결합기의 입출력 광도파로 사이에 광결합이 없는 삼각형 링 공진기)

  • Kim, Doo-Gun;Kim, Hyo-Jin;Kim, Seon-Hoon;Ki, Hyun-Chul;Kim, Hwe-Jong;Oh, Geum-Yoon;Choi, Young-Wan
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.1
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    • pp.123-128
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    • 2010
  • We have investigated the properties of the novel triangular ring resonator with the total internal reflection mirrors and the semiconductor optical amplifier for photonic integrated circuits (PIC). A novel triangular resonators containing active and passive sections are fabricated and characterized with various multimode interference (MMI) lengths. The optimum MMI length and width turn out to be 108 and 9 ${\mu}m$, respectively. A free spectral range of approximately 228 GHz is observed near 1558 nm along with an on-off ratio of 9 dB. The proposed triangular resonator has a good advantage to remove the direct coupling between the two access waveguides of the MMI coupler. Hence, such resonators can be directly integrated with other devices making compact and highly functional PIC possible.

Realization of Plasmonic Adaptive Coupler using Curved Multimode Interference Waveguide (곡면형 다중모드 간섭 도파로를 사용한 플라즈마 적응 결합기의 구현)

  • Ho, Kwang-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.2
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    • pp.165-170
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    • 2016
  • Nano-scale power splitter based on curved plasmonic waveguides are designed by utilizing the multimode interference (MMI) coupler. To analyze easily the adaptive properties of plasmonic curverd multimode interference coupler(PC-MMIC), the curved form transforms equivalently into a planar form by using conformal transformation method. Also, effective dielectric method and longitudinal modal transmission-line theory are used for simulating the light propagation and optimizing the structural parameters at 3-D guiding geometry. The designed $2{\times}2$ PC-MMIC does not work well for quasi-TM mode case due to the bending structure, and it does not exist 3dB coupling property, in which the power splitting ratio is 50%:50%, for quasi-TE mode case. Further, the coupling efficiency is better when the signal is incident at channel with large curvature radius than small curvature radius.

Implementation of Novel Bio-sensor Platform based on Optical MMI and Directional Coupler (광 MMI와 방향성 결합기에 기초한 새로운 바이오 센서 플랫폼의 구현)

  • Kwang-Chun Ho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.2
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    • pp.163-168
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    • 2023
  • In this paper, a novel platform for chemical sensing and biosensing is presented. The working principle is based on the coupling efficiency and interference properties of optical directional coupler (DC) and multimode interference coupler (MMIC). It has been realized using planar technology to allow integration on a silicon substrate. Firstly, the dispersion curves of DC and MMIC is described, and the design specification of an optimized slot optical waveguide to increase waveguide sensitivity is selected. Next, the sensor response to the refractive index change of sensing analyte is numerically simulated. The numerical results reveal that high effective index change per refractive index unit (RIU) change of analyte is obtained, and the sensitivity can be tuned using the DC and MMIC design technique.

Integrated Optical Waveguide Isolator Based Multimode Interference Using Magnetooptic Characteristics (자기 광학적 특성을 이용한 다중 모드 간섭에 기반한 집적 광 도파로 아이솔레이터)

  • Yang, Jeong-Su
    • Journal of the Korean Magnetics Society
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    • v.15 no.2
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    • pp.148-152
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    • 2005
  • A novel interferometric isolator has been proposed and designed to fabrticate waveguide magnetooptic isolator operating at a wavelength of $1.55{\cal}um$. The device consists of MMI (multimode interference) couplers and has a magnetooptic guiding layer with different layer structure in arms of the inteferometer. The layer structures in the arms of inteferometer are $HfO_2/CeY_2Fe_5O_{12}/NOG$ and $SiO_2/CeY_2Fe_5O_{12}/NOG$, respectively. This configuration give rise to different nonreciprocal phase shift. In consequence, the isolator operates under a unidirectional magnetic field. The optimized structure of the isolator was determined by a 3D beam propagation method.

Numerical Investigation on Propagation Characteristics of Novel Grating-Assisted MMI Coupler (새로운 격자 구조형 다중모드 간섭 결합기의 전파특성에 관한 수치 해석적 고찰)

  • Ho, Kwang-Chun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.45 no.11
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    • pp.29-34
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    • 2008
  • The propagation characteristics of novel grating-assisted multimode interference (GA-MMI) coupler are explicitly and theoretically investigated by using longitudinal modal transmission-line theory (L-MTLT). The coupling efficiency of GA-MMI coupler is evaluated along the variation of grating thickness and duty cycle, and the spectrum is analyzed numerically. The numerical results reveal that the coupling length and the efficiency of $2{\times}2$ GA-MMI coupler along the variation of grating structure have low tolerance and the bandwidth varies dramatically along the output states.

Vertical Coupling of Polymeric Double-Layered Waveguides Using a Stepped MMI Coupler

  • Lee, Jong-Moo;Ahn, Joon-Tae;Cho, Doo-Hee;Ju, Jung-Jin;Lee, Myung-Hyun;Kim, Kyong-Hon
    • ETRI Journal
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    • v.25 no.2
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    • pp.81-88
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    • 2003
  • We designed a multimode interference (MMI) coupler to use in vertical coupling of double layered polymeric waveguides and analyzed the coupling characteristics by comparing our experimental and simulation results. We found that our proposed new structure, a stepped MMI coupler, is effective in vertical coupling between waveguide layers with a short length of MMI and has a high tolerance for the variation in the structure of an MMI coupler that can be induced as errors in the fabrication process.

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Nano-scale Power Splitters by using Plasmonic Multimode Interference Couplers (플라즈마 다중모드 간섭 결합기를 사용한 나노 크기의 전력분배기)

  • Ho, Kwang-Chun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.4
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    • pp.47-52
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    • 2011
  • Nano-scale power splitter based on Si plasmonic waveguides are designed by utilizing the multimode interference (MMI) coupler. Effective dielectric method and longitudinal modal transmission-line theory are used for simulating the light propagation and optimizing the structural parameters at 3-D guiding geometry. The designed $1{\times}2$ 50:50 MMI power splitter has a nano-scale size of only $800nm{\times}850nm$. In order to achieve a variable power splitting ratio, a $2{\times}2$ MMI coupler is designed and the corresponding power splitting ratio can be tuned in the range of 78.5%:15.5%~5.5%:86.6%. Also, it is shown that it has a large bandwidth of $1.5{\mu}m{\sim}1.7{\mu}m$. In this range, the transmission is over 0.8.