• Title/Summary/Keyword: Gain saturation

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A Numerical Analysis of the Amplification Properties of the Regenerative Amplifier (재생증폭기의 증폭특성에 관한 수치해석)

  • 김남희;김병태
    • Korean Journal of Optics and Photonics
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    • v.5 no.1
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    • pp.67-73
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    • 1994
  • The simulation code was developed to analyze the amplification properties of the regenerative amplifier, such as gain narrowing, nonlinear effect, and energy saturation. To reduce gain narrowing in the regenerative amplifier, the input pulse with a symmetrical shape and the same center wavelength of the active medium should be amplified in the active medium with a broad fluorescence linewidth. In this respect, Ti:Sapphire with a low nonlinear refractive index, a high saturation fluence, and a broad fluorescence linewidth is the most appropriate medium for the regenerative amplifier. The knowledge and the important parameters were acquired for the optimum design of the regenerative amplifier.

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The effect comparison using saturation tone signals for optical wavelength division multiplexing communications (32 채널 파장분할다중화 광통신 전송에서 이득포화 광신호 영향 비교)

  • Choi, Bo-Hun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.8
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    • pp.2037-2042
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    • 2014
  • Three methods for gain saturation tone application were compared for optical wavelength division multiplexing transmission using more than 32 channels. The methods are to use high power distributed feedback laser diodes, to use amplified light sources, and lastly to use one saturation tone and several WDM light sources. 1532.3 nm, 1545.7 nm, and 1558.2 nm for the wavelength dependency of the saturation tone were also compared. As a result, the effect of amplified spontaneous emission noise caused by an amplifier was very slight. long wavelength for a saturation tone caused 1 dB gain reduction and its reason was analyzed.

Structural dependence of a gain saturation and noise figure in a traveling-wave semiconductor optical amplifier (진행파형 반도체 광증폭기에서 이득포화 및 잡음특성의 활성층 구조 의존성)

  • Jang, Se-Yun;Sim, Jong-In;Lee, Jeong-Seok;Kim, Ho-In;Yun, In-Guk;Kim, Seung-U;Sin, Hyeon-Cheol;Eo, Yeong-Seon
    • Proceedings of the Optical Society of Korea Conference
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    • 2004.02a
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    • pp.312-313
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    • 2004
  • The optical gain saturation and noise figure characteristics of 1550nm traveling-wave semiconductor optical amplifiers are analyzed experimentally and theoretically. The result shows that there is an optimum active layer thickness for high saturation output power and low noise figure.

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Linearization Up to the Saturation Region of Poller Amplifiers (전력증폭기 포화영역까지의 선형화)

  • 민이규;이상설
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.2
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    • pp.146-154
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    • 2002
  • This paper presents a linearization technique up to the saturation region of power amplifiers. The predistorter gain polynomials which have optimum coefficients are introduced. Power amplifiers are most efficient when operated near the saturation region. Compensating the amplifier nonlinearities with these predistorter gain polynomials, the efficiency of the amplifier can be maximized. Simulation results demonstrate that the adjacent channel power ratio (ACPR) is improves by about 63 ㏈ at the band edge. The convergence and reconvergence characteristics of the linearizer are also satisfactory.

Anti-Windup Controller Design for the Ship with the Rudder Saturation (Rudder 엑츄에이터 포화특성을 고려한 Anti-Windup 제어계의 설계)

  • 김영복;최명수
    • Journal of Ocean Engineering and Technology
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    • v.16 no.4
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    • pp.61-69
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    • 2002
  • In the actual control systems, there exist many kinds of restrictions or nonlinearities. However, due to the nonlinearities in actuators and sensors, the designed controller may not be applicable in some practical situations. One such nonlinearity is amplitude saturation in actuators. Although sometimes it may be ignored, in other cases failure to consider actuator saturation may severely degrade closed-loop system performance and even lead to instability. On the other hand, limiting the controller gain to avoid saturation sacrifices control effort and may lead to loss of performance. Consequently, in some cases, the actuator saturation must be explicitly taken into account to ensure desired performance. However, in this paper, an anti-windup control system design method is introduced to suppress the windup due to the amplitude saturation of the actuator. The proposed control system has very simple design process and guarantees the good control performance. The validity of the proposed control system will be shown by comparing with the results of a reported paper.

Stabilization of Saturation Nonlinearity System using Describing Functions (기술함수를 사용한 포화 비선형성 시스템의 안정화)

  • Song, Ja-Youn
    • Proceedings of the KIEE Conference
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    • 2002.07d
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    • pp.2043-2045
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    • 2002
  • When the input is small, increase of the input leads to a corresponding increase of output, but when the input reaches a certain level, its further increase does produces little or no increase of the output. When this phenomenon happens, the device is said to be in saturation. Occurence of saturation amounts to reducing the gain of the device as the input signals are increased. An extreme case of saturation is the on-off or relay nonlinearity. On-off nonlinearitics have effects similar to those of saturation nonlinearities. Furthermore they can lead to "chattering" in the physical systems doc to their discontinuous nature. This paper presents stabilization method of saturation nonlinearity system using deadzone describing function etc.. And computer simulation results show that saturation nonlinearity can be eliminated due to deadzone nonlinearity.

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D-band Stacked Amplifiers based on SiGe BiCMOS Technology

  • Yun, Jongwon;Kim, Hyunchul;Song, Kiryong;Rieh, Jae-Sung
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.2
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    • pp.276-279
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    • 2015
  • This paper presents two 3-stage D-band stacked amplifiers developed in a $0.13-{\mu}m$ SiGe BiCMOS technology, employed to compare the conventional cascode topology and the common-base (CB)/CB stacked topology. AMP1 employs two cascode stages followed by a CB/CB stacked stage, while AMP2 is composed of three CB/CB stacked stages. AMP1 showed a 17.1 dB peak gain at 143.8 GHz and a saturation output power of -4.2 dBm, while AMP2 showed a 20.4 dB peak gain at 150.6 GHz and a saturation output power of -1.3 dBm. The respective power dissipation was 42.9 mW and 59.4 mW for the two amplifiers. The results show that CB/CB stacked topology is favored over cascode topology in terms of gain near 140 GHz.

Design of $H_{\infty}$ Controllers for Linear Systems with Input Saturation (입력 포화 특성을 갖는 선형 시스템의 $H_{\infty}$ 제어기 설계)

  • Song, Yong-Heui;Kim, Jin-Hoon
    • Proceedings of the KIEE Conference
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    • 2002.07d
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    • pp.2040-2042
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    • 2002
  • In this paper, we consider the design of gam scheduled controllers for linear systems with input saturation. We obtain a reachable set and a control gain, which guarantees that the controls are never saturated inside this reachable set and that the $L_2$ gain is minimized, from matrix inequalities. This proposed gain scheduled control gives better performance than that of static control case, and we present the simulation results to show the usefulness of the proposed control.

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Impact of the Gain-saturation Characteristic of Erbium-doped Fiber Amplifiers on Suppression of Atmospheric-turbulence-induced Optical Scintillation in a Terrestrial Free-space Optical Communication System

  • Jeong, Yoo Seok;Kim, Chul Han
    • Current Optics and Photonics
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    • v.5 no.2
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    • pp.141-146
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    • 2021
  • We have evaluated the suppression effect of atmospheric-turbulence-induced optical scintillation in terrestrial free-space optical (FSO) communication systems using a gain-saturated erbium-doped fiber amplifier (EDFA). The variation of EDFA output signal power has been measured with different amounts of gain saturation and modulation indices of the optical input signal. From the measured results, we have found that the peak-to-peak power variation was decreased drastically below 2 kHz of modulation frequency, in both 3-dB and 6-dB gain compression cases. Then, the power spectral density (PSD) of optical scintillation has been calculated with Butterworth-type transfer function. In the calculation, different levels of atmospheric-turbulence-induced optical scintillation have been taken into account with different values of the Butterworth cut-off frequency. Finally, the suppression effect of optical scintillation has been estimated with the measured frequency response of the EDFA and the calculated PSD of the optical scintillation. From our estimated results, the atmospheric-turbulence-induced optical scintillation could be suppressed efficiently, as long as the EDFA were operated in a deeply gain-saturated region.

A novel anti-windup compensation for systems with saturating actuator (포화 요소가 있는 계를 위한 와인드업 방지 보상 방법)

  • 장원욱;박영진
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.299-304
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    • 1991
  • A novel approach based on a nonlinear compensator is proposed to prevent 'windup', which is caused by the saturation of the actuator and the integration action of the controller. The anti-windup compensator is located between the conventional linear controller, designed neglecting the saturation, and the actuator. It was proven based on the describing function method that, if the closed loop control systems are stable assuming no saturation, then there exist a range of compensator gain which prevents any limit-cycle and hence, guarantees the system stability. The computer simulation results show that the compensator proposed in the manuscript can eliminate unstable limit cycle and improve the transient response.

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