共查询到20条相似文献,搜索用时 10 毫秒
1.
ZHANG Zai-xuan DAI Bi-zhi WANG Jian-feng LIU Hong-lin XU Hai-feng GENG Dan LI Lan-xiao LI Chen-xia INSOO S. KIM 《光电子快报》2007,3(5):339-341
An S band and a C band distributed fiber Raman amplifiers (DFRAs) with flattened gain and compensated dispersion have been studied and implemented with 1427 nm and 1455 nm mono-wavelength fiber Raman lasers as the pumped sourcesrespectively. The gain of single-wave pumped S band and C band can reach 10 dB and 15 dB respectively. And a 50 nmgain flattened width was successfully obtained by using a chirp fiber Bragg grating (CFBG) gain flattened filter with gainripple of ±0.6 dB. The C band DFRA has been applied to CDMA wireless communication system successfully. 相似文献
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Experimental results obtained from supercritical c.w. GaAs transferred-electron reflection amplifiers at about 34 GHz are reported. Gains in excess of 20 dB have been observed with typical (gain)?×bandwidth products of 1.0?1.5GHz. The best noise figure is 18 dB, and this parameter is shown to be sensitive to the doping profile. The output power for 1 dB gain compression is typically 2.5?3.0 mW. 相似文献
3.
P. Vorreau D.C. Kilper C.A. White 《Photonics Technology Letters, IEEE》2005,17(7):1405-1407
The gain saturation of optical amplifiers due to changes in wavelength-division-multiplexed channel loading is characterized using a technique that determines the saturation effect on each channel. This channel gain saturation (CGS) measurement is applied to a broad-band backward-pumped Raman amplifier and used to study how the CGS spectral tilt is controlled by the relative contributions of the pump-to-pump and channel-to-channel interactions. The CGS is also used to measure the gain dependence on the channel add-delete pattern. 相似文献
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In this letter, a simple algorithm for the gain spectrum adjustment of backward-pumped distributed fiber Raman amplifier (B-DFRA) is demonstrated both theoretically and experimentally. It is shown that the change in pump power and corresponding change in gain spectrum are approximately related through a linear matrix, while the elements of the matrix can be easily measured. Feasibility of this algorithm is approved by experiment: a gain ripple of less than 1.2 dB across the C + L band is achieved during net gain adjustment from -15 dB to -9 dB of a 160-channel B-DFRA by varying the launched power of four pumping LDs. 相似文献
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The effects of stimulated Brillouin scattering (SBS) on Raman gain are explored. Measurements of gain in a fiber Raman amplifier show a saturation at low gain levels. Experimental data and a theoretical model are presented, demonstrating that this saturation is due to pump depletion by SBS. This effect also leads to Raman gain fluctuations arising from mode partitioning in a multimode pump laser. Two ways to avoid the deleterious effects of SBS on the performance of Raman amplifiers are suggested. One is to use a multimode semiconductor laser with a modal linewidth of the order of a few hundred megahertz, which leads to a strongly reduced Brillouin gain coefficient. The second approach is to use very short pump pulses in a backward configuration 相似文献
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The erbium-doped fiber amplifier noise figure spectrum and its evolution under various pumping regimes is analyzed. The analysis shows that noise figures in the range ±0.15 dB around the 3-dB quantum limit are possible within a spectral band of 50 nm. This demonstrates the possibility of quantum-limited amplification for broadband wavelength-division multiplexed (WDM) signals 相似文献
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Many radio-frequency circuits use differential topologies, whereas the instruments to evaluate them are inevitably single ended. Taking into account noise correlations, this work extends Friis' well-known equation for the noise figure of a cascade of two-ports to the case of three-ports, such as baluns, which surround a differential amplifier during measurements. The amplifier gain and noise figure may be accurately de-embedded with single-ended measurements on the cascade and on the baluns. The new formulas are experimentally validated 相似文献
10.
L.L. Wang B.C. Hwang L.M. Yang 《Photonics Technology Letters, IEEE》2003,15(5):664-666
Gain transients in both copumped and counterpumped distributed Raman amplifiers were investigated as a function of signal launch power, fiber type, and surviving signal wavelength for the first time. We found that gain transients are much more pronounced in a copumping scenario than in a counterpumping scenario for the same operating conditions. We also found that the dependency of gain transients on signal launch power, fiber type, and surviving channel wavelength follows the pump-depletion theory. A simple transient suppression technique with better than 0.2-dB ripple capability was also demonstrated. 相似文献
11.
Movassaghi M. Jackson M.K. Smith V.M. Hallam W.J. 《Lightwave Technology, Journal of》1998,16(5):812-817
We have developed a simple electrical noise figure measurement technique for the characterization of optical amplifiers. By subtracting the results of noise measurements at identical detected power levels made with and without the amplifier present, we are able to achieve an accuracy of ±0.3 dB in measured noise figure. Using this technique we obtain an excellent agreement between electrically and optically measured noise figures for two 98O-nm-pumped, copropagating erbium-doped fiber amplifiers (EDFA's) operating in saturation 相似文献
12.
A. Durecu-Legrand C. Simonneau D. Bayart A. Mussot T. Sylvestre E. Lantz H. Maillotte 《Photonics Technology Letters, IEEE》2005,17(6):1178-1180
Electrical measurements of the noise figure of a fiber-optical parametric amplifier are presented and compared with optical measurements. The transfer of pump noise by four-wave mixing was clearly demonstrated. A numerical model was developed to simulate the transfer of pump noise and validated by these measurements. Using this model, we determine, for practical systems, a minimum required pump optical signal-to-noise ratio of 65 dB. 相似文献
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S. Gupta Li Qian 《Photonics Technology Letters, IEEE》2004,16(9):2030-2032
We report a unique low-cost technique for measuring gain and noise figure (NF) in erbium-doped fiber amplifiers using a broad-band amplified spontaneous emission source and a transmission filter, by extracting the slope and intercept of output power spectral density versus input power spectral density at filter edges. The required filter depth is 30 dB. Discrepancies of /spl les/0.3 dB are found between gain or NF obtained from this technique and those measured using conventional spectral-interpolation technique employing multiple lasers at 100-GHz spacing across the C-band. 相似文献
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Amplified spontaneous Raman scattered light power in forward and backward Raman amplifiers is theoretically and experimentally studied under the assumption of the constant Raman gain coefficient in the bandwidth of an optical filter. On the basis of the results, the power ratio of the amplified signal to amplified spontaneous scattering is discussed. As a result, it is clarified that the effect of amplified spontaneous Raman scattering on the signal to noise ratio for backward Raman scattering is larger than for forward Raman scattering. 相似文献
15.
The noise figure and gain characteristics of lossless and lossy MESFET distributed amplifiers have been theoretically investigated by various workers. In the letter, in order to support previously reported theoretical results, the experimentally measured noise figure and power gain performance of two-stage and five-stage hybrid microwave distributed amplifiers employing MESFETs are presented. The measured results are compared to theoretically obtained values and found to be in reasonable agreement over most of the band. 相似文献
16.
A. Kobyakov M. Vasilyev S. Tsuda G. Giudice S. Ten 《Photonics Technology Letters, IEEE》2003,15(1):30-32
We derive an exact and a closed-form approximate analytic formula for effective lumped Raman noise figure in backward-pumped dispersion-managed fibers (DMFs) of arbitrary topology. Within the single-pump small-signal amplification model, important effects such as unequal loss coefficients at pump and signal wavelengths or splice loss for the pump and the signal between the DMFs' sections are taken into account. Theoretical results agree well with the noise figure measured in a symmetric DMF. The developed approach can be used to optimize the noise performance of DMFs. 相似文献
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根据喇曼放大器的增益和噪声的定义,提出一种独特的低成本的测量噪声和增益的方法.该方法是用一个梳状滤波器对宽带ASE信号进行调制,并在输入和输出信号的凹陷的较陡处进行取点,从而得出某个局部的输入和输出信号的线性关系,进一步计算出光纤喇曼放大器的增益和噪声系数.对该方法进行了数值模拟,以便进一步阐明测量原理. 相似文献
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喇曼光纤放大器的几项关键技术 总被引:1,自引:0,他引:1
喇曼光纤放大器具有优越的宽带性能 ,是现代宽带通信的较理想放大器。它的实用化得益于一些关键性技术的发展。对喇曼光纤放大器的最新发展进行了研究 ,对其中的关键性技术进行了分析、对比 ,以期有利于今后的实用化研制工作 相似文献
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The spectrum of amplified spontaneous Raman scattering and gain in a fiber Raman amplifer has been calculated analytically as a function of distance and pump power. The model used makes no assumptions on the magnitude of the gain and considers the pump nondepletion region. From the results, the on/off ratio has been calculated and is found to have a variation with length that depends on frequency detuning. An enhancement in on/off ratio is also found for small fiber lengths but at limited gain. The use of a narrow-bandpass optical fiber leads to quite different behavior of the on/off ratio than for the unfiltered case. 相似文献