• Title/Summary/Keyword: fiber amplifier

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Wideband Gain Flattened Hybrid Erbium-doped Fiber Amplifier/Fiber Raman Amplifier

  • Afkhami, Hossein;Mowla, Alireza;Granpayeh, Nosrat;Hormozi, Azadeh Rastegari
    • Journal of the Optical Society of Korea
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    • v.14 no.4
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    • pp.342-350
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    • 2010
  • An optimal wideband gain flattened hybrid erbium-doped fiber amplifier/fiber Raman amplifier (EDFA/FRA) has been introduced. A new and effective optimization method called particle swarm optimization (PSO) is employed to find the optimized parameters of the EDFA/FRA. Numerous parameters which are the parameters of the erbium-doped fiber amplifier (EDFA) and the fiber Raman amplifier (FRA) define the gain spectrum of a hybrid EDFA/FRA. Here, we optimize the length, $Er^{3+}$ concentration, and pump power and wavelength of the EDFA and also pump powers and wavelengths of the FRA to obtain the flattest operating gain spectrum. Hybrid EDFA/FRA with 6-pumped- and 10-pumped-FRAs have been studied. Gain spectrum variations are 1.392 and 1.043 dB for the 6-pumped- and 10-pumped-FRAs, respectively, in the 108.5 km hybrid EDFA/FRAs, with 1 mW of input signal powers. Dense wavelength division multiplexing (DWDM) system with 60 signal channels in the wavelength range of 1529.2-1627.1 nm, i.e. the wide bandwidth of 98 nm, is studied. In this work, we have added FRA's pump wavelengths to the optimization parameters to obtain better results in comparison with the results presented in our previous works.

A Study of the Transient Effect at the Thulium-doped Optical Fiber Amplifier (Thulium이 도핑된 광섬유 증폭기의 과도현상에 관한 연구)

  • 이재명;이영우
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2001.10a
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    • pp.349-352
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    • 2001
  • The transient response in TDFA(Thulium-Doped Fiber Amplifier) is theoretically investigated. The TDFA has the spectral gain band in 1.47 ${\mu}{\textrm}{m}$. The transient model includes the transient buildup of the population inversion, the pump power, the signal power and their transient variation along the fiber amplifier. The results of numerical analysis can predict the gain saturation and recovery time at the fiber amplifier. It also shows the gain saturation and recovery effect depending on the pumping and saturation rate.

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Wideband Hybrid Fiber Amplifier Using Er-Doped Fiber and Raman Medium

  • Seo, Hong-Seok;Ahn, Joon-Tae;Park, Bong-Je;Chung, Woon-Jin
    • ETRI Journal
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    • v.29 no.6
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    • pp.779-784
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    • 2007
  • In this paper, we report the experimental results of a hybrid wideband fiber amplifier. The amplifying medium is a concatenated hybrid fiber consisting of Er-doped fiber (EDF) and dispersion compensating fiber (DCF). The gain mechanisms are based on stimulated emission in the EDF and stimulated Raman scattering (SRS) in the DCF. Since we simultaneously use optical amplification by the two processes, the gain bandwidth is easily expanded over 105 nm by a two-tone pumping scheme. Using an experimental setup constructed with a hybrid structure of EDF-DCF-EDF, we analyzed the spectral behavior of amplified spontaneous emission for pumping powers. We achieved an optical gain of over 20 dB in the wavelength range from 1,500 to 1,600 nm under optimized pumping conditions to make the spectral gain shape flat.

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Investigation of Amplifying Mechanism in an t-Band Erbium-Doped Fiber Amplifier Pumped by a 980 nm Pump

  • Lee, Dong-Han;Lee, Han-Hyub;Oh, Jung-Mi;Kim, Byung-Jun
    • Journal of the Optical Society of Korea
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    • v.7 no.2
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    • pp.67-71
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    • 2003
  • For a more detailed understanding of the mechanism of an L-band erbium-doped fiber amplifier, we investigated 980 nm absorption, signal amplification and forward and backward amplified spontaneous emission along the erbium-doped fiber. In addition, we compared performances of the erbium-doped fiber amplifier with and without a fiber Bragg grating.

3.2-kW 9.7-GHz Polarization-maintaining Narrow-linewidth All-fiber Amplifier

  • Hang Liu;Yujun Feng;Xiaobo Yang;Yao Wang;Hongming Yu;Jue Wang;Wanjing Peng;Yanshan Wang;Yinhong Sun;Yi Ma;Qingsong Gao;Chun Tang
    • Current Optics and Photonics
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    • v.8 no.1
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    • pp.65-71
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    • 2024
  • We present a Yb-doped narrow-linewidth polarization-maintaining all-fiber amplifier that achieves a high mode-instability (MI) threshold, high output power, and 9.7-GHz spectral linewidth. Six wavelength-multiplexed laser diodes are used to pump this amplifier. First, we construct a high-power fiber amplifier based on a master oscillator-power amplifier configuration for experiments. Subsequently, we examine the MI threshold by individually pumping the amplifier with wavelengths of 976, 974, 981, 974, and 981 nm respectively. The experimental results demonstrate that the amplifier exhibits a high MI threshold (>3.5 kW) when pumped with a combination of wavelengths at 974 and 981 nm. Afterward, we inject an optimized phase-modulated seed with a nearly flat-top spectrum into this amplifier. Ultimately, laser output of 3.2 kW and 9.7 GHz are obtained.

Real-time Adaptive Polarization Control in a Non-PM Fiber Amplifier

  • Kyuhong, Choi;Jinju, Kim;Dal Yong, Lee;Changsu, Jun
    • Current Optics and Photonics
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    • v.7 no.1
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    • pp.33-37
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    • 2023
  • Real-time adaptive control of laser output polarization is presented in a 10-W-level non-polarization-maintaining (non-PM) fiber amplifier. While the output polarization from a non-PM fiber amplifier tends to be irregular, depending on output power, time, and perturbation, closed-loop polarization control can maintain the polarization extinction ratio at higher than 20 dB. Real-time polarization control can attain the target linear polarization mostly within 1.4-25 ms and shows stability against external perturbations. This approach can satisfy both linear polarization and high output power in a non-PM amplifier, and facilitates optimization of laser performance and maintenance-free operation.

Design of Hybrid Optical Amplifiers for High Capacity Optical Transmission

  • Kim, Seung-Kwan;Chang, Sun-Hyok;Han, Jin-Soo;Chu, Moo-Jung
    • ETRI Journal
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    • v.24 no.2
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    • pp.81-96
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    • 2002
  • This paper describes our design of a hybrid amplifier composed of a distributed Raman amplifier and erbium-doped fiber amplifiers for C- and L-bands. We characterize the distributed Raman amplifier by numerical simulation based on the experimentally measured Raman gain coefficient of an ordinary single mode fiber transmission line. In single channel amplification, the crosstalk caused by double Rayleigh scattering was independent of signal input power and simply given as a function of the Raman gain. The double Rayleigh scattering induced power penalty was less than 0.1 dB after 1000 km if the on-off Raman gain was below 21 dB. For multiple channel amplification, using commercially available pump laser diodes and fiber components, we determined and optimized the conditions of three-wavelength Raman pumping for an amplification bandwidth of 32 nm for C-band and 34 nm for L-band. After analyzing the conventional erbium-doped fiber amplifier analysis in C-band, we estimated the performance of the hybrid amplifier for long haul optical transmission. Compared with erbium-doped fiber amplifiers, the optical signal-to-noise ratio was calculated to be higher by more than 3 dB in the optical link using the designed hybrid amplifier.

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Simulation and Experimental Validation of Gain-Control Parallel Hybrid Fiber Amplifier

  • Ali, Mudhafar Hussein;Abdullah, Fairuz;Jamaludin, Md. Zaini;Al-Mansoori, Mohammed Hayder;Al-Mashhadani, Thamer Fahad;Abass, Abdulla Khudiar
    • Journal of the Optical Society of Korea
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    • v.18 no.6
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    • pp.657-662
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    • 2014
  • We demonstrate a simulation of a parallel hybrid fiber amplifier in the C+L-band with a gain controlling technique. A variable optical coupler is used to control the input signal power for both EDFA and RFA branches. The gain spectra of the C+L-band are flattened by optimizing the coupling ratio of the input signal power. In order to enhance the pump conversion efficiency, the EDFA branch was pumped by the residual Raman pump power. A gain bandwidth of 60 nm from 1530 nm to 1590 nm is obtained with large input signal power less than -5 dBm. The gain variation is about 1.06 dB at a small input signal power of -30 dBm, and it is reduced to 0.77 dB at the large input signal power of -5 dBm. The experimental results show close agreement with the simulation results.

Regenerative Erbium-Doped Fiber Ring Amplifier with Unidirectional and Bi-directional Feedbacks

  • Shah, N.S.Mohd.;Teyo, T.C.;Poopalan, P.;Ahmad, H.
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.540-541
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    • 2002
  • In this paper, the performance of upidirectional and hi-directional regenerative erbium-doped fiber amplifier (EDFA) is compared. The systems are operating above laser oscillation threshold. The experimental results show that the unidirectional regenerative EDFA has a better performance than the hi-directional.

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The effect of gain recovery at the optical fiber amplifier by the input pulse train (광섬유 증폭기에서의 입력 펄스 열에 의한 Cain Recovery 특성)

  • 이재명;이영우
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.3
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    • pp.459-463
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    • 2002
  • We studied the effect of gain recovery at the optical fiber amplifier by the input pulse trains We also theoretically analyzed the limitation of the saturation and recovery time for the PDFA(Praseodymium-Doped Fiber Amplifier) which has the spectral gain at 1.3${\mu}{\textrm}{m}$ band. We can predict the interval between the pulse train, pump power, and the effect of the saturation and recovery time which is affected to the amplification of the optical pulse.