• Title, Summary, Keyword: AWG

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Design and Performance Evaluation of Hybrid Two-Stage AWG based WDM-PON Architecture (혼합형 2단 AWG 기반의 WDM-PON 구조 설계 및 성능평가)

  • Han Kyeong-Eun;Lee Seung-Hyun;Kim Young-Chon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.7B
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    • pp.573-582
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    • 2006
  • In this paper, we propose a hybrid two-stage AWG-based WDM-PON architecture in order to overcome the limitations of the existing PONs and single AWG-based WDM-PONs as well as to accomodate the new services and the expandability of network. The proposed architecture employs two-stage AWG for downstream transmission and single AWG and combiners for upstream one at RN. It also employs the separated fiber with multi-wavelength for both direction. It leads to high scalability, low cost, and high capacity for transmission. In downstream transmission, the transparency can be guaranteed since the traffic is transmitted to ONU through each channel. However, several ONUs share the channel for upstream one by using WDM/TDMA scheme because the asymmetrical feature of networks is considered. The performance of the proposed one is evaluated and compared with other architectures in terms of cost, network capacity and up/downstream bandwidth.

Measurement of the Phase Errors of AWG by Using the Monte-Carlo Analysis (몬테카를로 분석 방법을 이용한 AWG의 위상 오차 측정)

  • Go, Chun-Soo;Oh, Yong-Ho;Lim, Sung-Woo
    • Korean Journal of Optics and Photonics
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    • v.22 no.5
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    • pp.207-213
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    • 2011
  • We propose a new method to measure the phase errors of an AWG(arrayed waveguide grating) through Monte-Carlo analysis. In the frequency domain method, we used the Monte-Carlo method to fit the theory to the experimental results. The phase and amplitude values are obtained from the fitted theory. To verify our method, we carried out a simulation. Some phase errors were included to make a virtual interferogram and we measured the actual AWG phase errors from it by our method. The results show that our method gives good results if the laser tuning range is larger than 1.7 times of the AWG FSR(free spectral range) and if the phase errors are within ${\pm}50^{\circ}$.

Low Coherence Interferometer for Measurement of Path Length Errors in Arrayed-Waveguide Grating (Arrayed-Waveguide Grating의 경로 오차 측정을 위한 저 간섭 광원 간섭계)

  • Song, Young-Ki;Heo, Nam-Chun;Chung, Young-Chul
    • Korean Journal of Optics and Photonics
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    • v.15 no.6
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    • pp.539-546
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    • 2004
  • An improved low coherence interferometer system and a new analysis method for the accurate measurement of the optical path difference error of an AWG (Arrayed-Waveguide Grating) are described. The use of software simplifies the experimental setup by eliminating the hardware (clock generator). In addition, the actual distances between the peak positions of the adjacent interference signals are calculated using interpolation methods. The wavelength transmission characteristics of the AWG are calculated assuming the measured phase errors. The calculated AWG characteristic is quite similar to the actual measurement result, confirming accuracy of the proposed measurement setup.

Athermalized Polymeric Arrayed-Waveguide Grating by Partial Detachment from a Si Substrate

  • Lee, Jong-Moo;Ahn, Joon-Tae;Park, Sun-Tak;Lee, Myung-Hyun
    • ETRI Journal
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    • v.26 no.3
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    • pp.281-284
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    • 2004
  • We demonstrate a new fabrication method for adjusting the temperature dependence of a polymeric arrayed-waveguide grating (AWG) on a Si substrate. A temperature-dependent wavelength shift of-0.1nm/$^{\circ}C$ in a polymeric AWG on a Si substrate is reduced of+0.1nm/$^{\circ}C$ by detaching part of the polymer film, including the grating channel region of the AWG, from the Si substrate while the other parts remain fixed on the substrate.

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Anti-inflammatory Effect of Arbitrary Waveform Generator Treatment in Rats

  • Kim, Myung-Gyou;Lee, Se-Na;Seo, Il-Bok;Leem, Kang-Hyun;Ham, Kee-Sun;Kim, Hye-Kyung
    • Biomedical Science Letters
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    • v.14 no.1
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    • pp.39-45
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    • 2008
  • Inflammation is the complex biological response of injured tissues to harmful stimuli. A cascade of biochemical events propagates and matures the inflammatory response, involving the local vascular system, the immune system, and various cells within the injured tissue. The immune system is often involved with inflammatory disorders, demonstrated in both allergic reactions and some myopathies, with many immune system disorders resulting in abnormal inflammation. An Arbitrary Waveform Generator (AWG) is a piece of electronic test equipment used to generate electrical waveforms for the treatment of patients. The patients with gastritis and arthritis have been known to have a relatively favorable prognosis with AWG treatment. Accordingly, we examined the effects of AWG treatment in gastritis and arthritis animal model. The compound 48/80 was used to induce animal gastritis model. The tissue malone dialdehyde (MDA) and serum histamine levels, and the activity of superoxide dismutase (SOD) in stomach tissue were measured. The tissue MDA and serum histamine levels in AWG treated groups exhibited the decreased tendency compared with control group, whereas the tissue SOD activity was slightly increased. The Freund's complete adjuvant was used to induce animal arthritis model as well. The paw edema volume and the width of ankle joint were determined. The AWG treatment significantly decreased the paw edema volume after 5th day of treatment. Although further studies should be performed to confirm the effects of AWG treatment, present study suggest that AWG treatment might be used as a complementary treatment for the gastritis or arthritis treatment.

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Design and fabrication of temperature-independent AWG-WDM devices using polymer overcladding (폴리머 상부클래드를 이용한 온도무의존 AWG 파장분할 다중화 소자의 설계 및 제작)

  • Han, Young-Tak;Kim, Duk-Jun;Shin, Jang-Uk;Park, Sang-Ho;Park, Yoon-Jung;Sung, Hee-Kyeng
    • Korean Journal of Optics and Photonics
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    • v.14 no.2
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    • pp.135-141
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    • 2003
  • In arrayed waveguide grating (AWG) devices whose waveguides were composed of polymer with negative thermo-optic coefficient as overcladding, and silica with positive thermo-optic coefficient as both core and undercladding, we investigated the temperature dependence of the central wavelength using two-dimensional SFDM. From these results, it was confirmed that the temperature dependence can be nearly eliminated by adjusting the refractive index of the cladding and the thickness of the silica thin film upper-loaded on the core. Based on the numerical calculations, the AWG device with polymer overcladding was fabricated. and its optical characteristics were compared with those of the orginal silica AWG device. The introduction of polymer overcladding decreased the temperature dependence of the central wavelength from 0.0130 nm/$^{\circ}C$ to 0.0028 nm/$^{\circ}C$ without deteriorating the insertion loss and crosstalk characteristics.

Alternative Method of AWG Phase Measurement Based on Fitting Interference Intensity

  • Oh, Yong Ho;Lim, Sungwoo;Go, Chun Soo
    • Journal of the Optical Society of Korea
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    • v.16 no.2
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    • pp.91-94
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    • 2012
  • Arrayed waveguide grating (AWG) phase errors are normally assessed from the Fourier transform of the interference intensity data in the frequency domain method. However it is possible to identify the phases directly from the intensity data if one adopts a trial-and-error method. Since the functional form of the intensity profile is known, the intensities can be calculated theoretically by assuming arbitrary phase errors. Then we decide the phases that give the best fit to the experimental data. We verified this method by a simulation. We calculated the intensities for an artificial AWG which is given arbitrary phases and amplitudes. Then we extracted the phases and amplitudes from the intensity data by using our trial-and-error method. The extracted values are in good agreement with the originally given values. This approach yields better results than the analysis using Fourier transforms.

Design of the Single-loop Voltage Controller for Arbitrary Waveform Generator (임의 파형 발생기를 위한 단일 루프 전압 제어기 설계)

  • Kim, Hyeon-Sik;Chee, Seung-Jun;Sul, Seung-Ki
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.1
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    • pp.58-64
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    • 2016
  • This study presents a design method for a single-loop voltage controller that is suitable for an arbitrary waveform generator (AWG). The voltage control algorithm of AWG should ensure high dynamic performance and should attain sufficient robustness to disturbances such as inverter nonlinearity, sensor noise, and load current. By analyzing the power circuit of AWG, control limitation and control target are presented to improve the dynamic performance of AWG. The proposed voltage control algorithm is composed of a single-loop output voltage control, an inverter current feedback term to improve transient response, and a load current feedforward term to prevent voltage distortion. The guideline for setting control gain is presented based on output filter parameters and digital time delay. The performance of the proposed algorithm is proven by experimental results through comparison with the conventional algorithm.

AWG device characteristic dependence on the fabrication error limit (도파폭 공정오차에 따른 광도파 특성변화와 소자성능 저하)

  • 박순룡;오범환
    • Korean Journal of Optics and Photonics
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    • v.10 no.4
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    • pp.342-347
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    • 1999
  • As the waveguide width and the radius of curvature get smaller for the effort of monolithic fabrication of integrated photonic devices, the waveguide characteristics change significantly according to the change of the waveguide width or the radius of curvature. Especially, variation of the waveguide width due to fabrication process errors induces a phase error for each waveguide from the change of the propagation constant. Therefore, it is important to quantify these variation effects on the device characteristics for the design and fabrication of highly integrated photonic devices. Here, we analyze four different types of waveguides to get general characteristics in propagation constant change by utilizing the effective index method and the analytic solution method. Futhermore, the output characteristics of two AWG(Arrayed Waveguide Grating) devices are simulated by a highly-functional computer code. The simulated results have been found to be similar to the realistic device characteristics. The required fabrication error limit for the ridge-type InP-AWG device should be smaller than 0.02 ${\mu}{\textrm}{m}$ to get better channel crosstalk than-25 dB, while the required fabrication error limit for rib-type silica-AWG devices may be allowed up to 0.1 ${\mu}{\textrm}{m}$ to obtain better crosstalk than -30 dB.

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