• Title/Summary/Keyword: Optical amplifiers

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Design of Low Power All-Optical Networks with Dynamic Lightpath Establishment

  • Hirata, Kouji;Ito, Kohei;Fukuchi, Yutaka;Muraguchi, Masahiro
    • Journal of Communications and Networks
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    • v.18 no.4
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    • pp.551-558
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    • 2016
  • In multifiber all-optical networks, optical amplifiers are used for amplifying multiple optical signals with different wavelengths in fibers. An optical amplifier operates when any of lightpaths passes through it. Therefore, it should simultaneously amplify as many lightpaths as possible for efficiently utilizing its power. This paper proposes a dynamic lightpath establishment scheme considering the use efficiency of the optical amplifiers and the depletion of the wavelength resources in multifiber all-optical networks. The proposed scheme provides a routing and wavelength assignment strategy that reduces both the power consumption of the optical amplifiers and the blocking probability of the lightpath establishment. Through simulation experiments, we demonstrate the effectiveness of the proposed scheme.

Performance Evaluation of Bidirectional Optical Amplifiers for Amplified Passive Optical Network Based on Broadband Light Source Seeded Optical Sources

  • Kang, Byoung-Wook;Kim, Chul-Han
    • Journal of the Optical Society of Korea
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    • v.15 no.1
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    • pp.4-8
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    • 2011
  • We have evaluated the performances of bidirectional optical amplifiers which were suited for the cost-effective implementation of amplified bidirectional passive optical networks (PONs). First, we measured the maximum gains of two simple bidirectional optical amplifiers implemented without using any optical components for the suppression of reflected signals. From the results, the maximum gains of two simple bidirectional amplifiers with a broadband light source (BLS) seeded optical source were limited to be 27 dB due to the reflection-induced in-band crosstalk, when the reflectance coefficients were measured to be -33 dB in both directions. Then, we have also implemented a bidirectional optical amplifier with two band splitters for the amplified bidirectional PON where the two different wavelength bands were allocated to the downstream and upstream signals transmission. In our measurement, we confirmed that the maximum gain of bidirectional optical amplifier with two band splitters could be increased to more than 30 dB owing to the efficient suppression of in-band crosstalk.

Filter-Free Wavelength Conversion Using Mach-Zehnder Interferometer with Integrated Multimode Interference Semiconductor Optical Amplifiers

  • Kim, Jong-Hoi;Kim, Hyun-Soo;Sim, Eun-Deok;Kim, Kang-Ho;Kwon, Oh-Kee;Oh, Kwang-Ryong
    • ETRI Journal
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    • v.26 no.4
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    • pp.344-350
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    • 2004
  • We propose a filter-free wavelength conversion using a Mach-Zehnder interferometer with monolithically integrated $2{\times}2$ multimode interference semiconductor optical amplifiers (MMI-SOAs). The device has been optimized by considering a non-homogeneous carrier distribution due to the self-imaging properties of the MMI-SOA. Static measurements show an extinction ratio of up to 18 dB and an input signal rejection ratio of up to 20 dB.

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A Study on the Transmission Length Limitation by Chromatic Dispersion in High Speed FOT스s (초고속 광파이버 전송시스템에서 색분산에 의한 전송거리 제한에 관한 연구)

  • 정은숙;김재평;정진호;김영권
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.4 no.3
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    • pp.18-29
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    • 1993
  • In single mode fiber optic transmission systems(FOT's) operated at high modulation rates over long fiber spans, chromatic dispersion can produce distortion in the demodulated waveforms, resulting in intersymbol interference(ISI) in the received signal and a reduction of transmission system performance. In this paper, chromatic dispersion limitations for intensity modulation and direct detection(IM-DD) systems are studied by considering the effect of phase modulation to amplitude modulation (PM-AM) conversion noise. Laser phase noise conversion to amplitude noise due to fiber chromatic dispersion is analyzed by deriving the noise power spectral density. We first derive the noise power spectral density of the laser phase noise to intensity noise conver- sion. Next, also evaluate the system power penalty and the transmitter laser linewidth required to avoid PM-AM conversion noise penalties in long-haul nonregenerative transmission system using an external modulator and optical amplifiers. For such system with optical amplifiers, transmission sys- tem length is limited due to fiber chromatic dispersion, even if an ideal external modulator is used.

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10 Gb/s all optical AND gate by using semiconductor optical amplifiers (반도체 광증폭기를 이용한 10 Gb/s 전광 AND논리소자)

  • Kim, Jae-Hun;Kim, Byung-Chae;Byun, Young-Tae;Jhon, Young-Min;Lee, Seok;Woo, Deok-Ha;Kim, Sun-Ho
    • Korean Journal of Optics and Photonics
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    • v.14 no.2
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    • pp.166-168
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    • 2003
  • By using gain saturation of semiconductor optical amplifiers (SOAs), an all-optical AND gate at 10 Gb/s has been successfully demonstrated. Firstly, Boolean (equation omitted) has been obtained using the first SOA with signal B and clock injection. Then, the all-optical AND gate is achieved using the second SOA with signals A and (equation omitted) injection.

Structural dependence of the effective facet reflectivity in spot-size-converter integrated semiconductor optical amplifiers (모드변환기가 집적된 반도체 광증폭기에서의 유효단면반사율의 구조 의존성)

  • 심종인
    • Korean Journal of Optics and Photonics
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    • v.11 no.5
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    • pp.340-346
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    • 2000
  • Traveling wave type semiconductor optical amplifiers integrated with spot-size-converter (SSC-TW-SOA) have been extensively studied for the improvement of coupling effiClency With single-mode fiber and fO! the cost reducClon 111 a packaging In tlIis paper the slructural dependence of the spot-slZe-converter on the effective facet reflectlvllY $R_{eff}$ was experimentally as well as thcoretienlly mvestlgated. It was shown that not only a sufficient mode-conversion in a sse region along the latersl and tran~verse directions but also an introductIOn of angled-facet were very essential in order to reduce $R_{eff}$ Very small ripple less than 0.1 dB in an amplified spontaneous emission spectrum was observed with the fabncated SSC-lW-SOA which consists of the wrndow length of $20\mu\textrm{m}$, facet angle of $7^{\circ}$, and antlrelleetioll-coated facet of ] % reflectivity.tivity.

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Analysis of Detuning-filter-assisted All-optical Wavelength Conversion Based on a Semiconductor Optical Amplifier with Strong Wavelength Dependence of Gain and Phase

  • Qin, Cui;Zhao, Jing;Yu, Huilong;Zhang, Jian
    • Current Optics and Photonics
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    • v.1 no.6
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    • pp.579-586
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    • 2017
  • In this paper, we theoretically demonstrate that semiconductor optical amplifiers (SOAs) with strong wavelength dependence of gain and phase are capable of all-optical inverted and non-inverted wavelength conversion (WC) over a wide range, with the assistance of an optical filter. First, the gain dynamics and phase dynamics in a common quantum well (QW) SOA with the $In_{0.53}Ga_{0.47}As/In_{0.7322}Ga_{0.2678}As_{0.5810}P_{0.4190}$ material system are found to be strongly dependent on wavelength, which is mainly related to the wavelength dependence of the differential gain and the differential refractive-index change. Second, the wavelength dependence in an all-optical wavelength converter based on the QW SOA cascaded with a detuning band pass filter is studied. Simulations show that the quality of the converted signal has little dependence on the operation wavelength. Both inverted and non-inverted WC can be achieved, over a large wavelength range. Therefore, although the gain and phase change are strongly wavelength-dependent, the effects of this dependence can be erased by appropriate optical filtering.

2.5 Gbit/s all-optical GR logic gate using semiconductor optical amplifiers (반도체 광증폭기(SOA)를 이용한 2.5 Gbit/s 전광 OR 논리 게이트)

  • Byun, Young-Tae;Kim, Jae-Hun;Jhon, Young-Min;Lee, Seok;Woo, Deok-Ha;Kim, Sun-Ho
    • Korean Journal of Optics and Photonics
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    • v.13 no.2
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    • pp.151-154
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    • 2002
  • All-optical OR logic gate is realized by use of gain saturation and wavelength conversion in the semiconductor optical amplifiers (SOA). It is operated by the nonlinearity of the SOA gain and hence to obtain the sufficient gain saturation of the SOA, pump signals are amplified by an Er-doped fiber amplifier (EDFA) at the input of the SOA. The operation characteristics of all-optical OR logic gate are successfully measured at 2.5 Gbit/s.