【摘要】：隨著信息化社會(huì)的發(fā)展,將人們從時(shí)空的束縛中得以解放。通信在整個(gè)社會(huì)的發(fā)展中扮演著不可忽略的角色。而光纖通信以其低干擾、大容量,長(zhǎng)距離、低損耗等優(yōu)勢(shì)承載著通信的骨干網(wǎng)絡(luò)。 隨著光纖通信系統(tǒng)的傳輸距離不斷增長(zhǎng),為了克服光纖自身的衰減損耗,要求必要的提高信號(hào)進(jìn)入光纖的初始光功率,但功率越高受激拉曼散射效應(yīng)越明顯,對(duì)系統(tǒng)性能影響越大。因此以摻鉺光纖放大器為主要代表的中繼放大器,在一定程度上緩解了功率矛盾。然而,摻鉺光纖放大器存在著成本高、帶寬窄等缺點(diǎn)。 此時(shí),光纖拉曼放大器,以其低成本、非線性失真小,增益帶寬幾乎無(wú)限,輸出功率高飽和,相對(duì)其他系統(tǒng)構(gòu)造簡(jiǎn)單等優(yōu)勢(shì),成為了長(zhǎng)距離、大容量的密集波分復(fù)用系統(tǒng)廣泛使用的理想技術(shù)。拉曼放大器,以受激拉曼散射效應(yīng)為放大原理,以系統(tǒng)光纖作為放大介質(zhì),利用高功率的短波長(zhǎng)光波作為泵浦對(duì)長(zhǎng)波長(zhǎng)、低功率信道的信息光波進(jìn)行全程放大。泵浦在對(duì)信號(hào)放大時(shí),并非等增益放大,而是受很多因素的影響,呈現(xiàn)出波動(dòng)狀態(tài),所以要求光纖通信系統(tǒng)在對(duì)放大信號(hào)的同時(shí)還需要考慮到信號(hào)增益的平坦化,使其信號(hào)在接收端的接收功率總體平穩(wěn)。 本文主要的研究重點(diǎn)如下：第一,在廣泛汲取前人對(duì)外拉曼放大相關(guān)研究基礎(chǔ)上,以光纖拉曼放大器系統(tǒng)的特點(diǎn)和應(yīng)用為重點(diǎn),介紹了拉曼放大器的工作原理和特性,引入拉曼放大器的理論模型,分析了系統(tǒng)放大增益與系統(tǒng)參數(shù)(信號(hào)初始功率,泵浦功率,光纖距離等)之間的關(guān)系。第二,深入分析了光纖通信系統(tǒng)的噪聲,建立相關(guān)噪聲的理論模型,并對(duì)雙重瑞利背向散射噪聲作了詳細(xì)的分析和研究,從理論上驗(yàn)證了前人的實(shí)驗(yàn)結(jié)果,得到了噪聲對(duì)系統(tǒng)影響以及與系統(tǒng)參數(shù)之間的數(shù)學(xué)關(guān)系。第三,以光纖拉曼放大器的傳輸耦合方程為基礎(chǔ),數(shù)值分析了泵浦及信號(hào)功率沿光纖的分布,借助改進(jìn)的粒子群優(yōu)化算法對(duì)放大系統(tǒng)的增益平坦度進(jìn)行了優(yōu)化,使得系統(tǒng)增益波動(dòng)從3dB提高到0.5dB。
[Abstract]:With the development of information society, people will be liberated from the bondage of time and space. Communication plays an important role in the development of the whole society. Optical fiber communication has the advantages of low interference, large capacity, long distance and low loss. With the increasing transmission distance of optical fiber communication system, in order to overcome the attenuation loss of fiber itself, it is necessary to increase the initial optical power of the signal into the fiber, but the higher the power is, the more obvious the stimulated Raman scattering effect is. The greater the impact on system performance. Therefore, the relay amplifier, mainly represented by erbium-doped fiber amplifier, alleviates the power contradiction to some extent. However, erbium-doped fiber amplifiers have some disadvantages, such as high cost and narrow band. In this case, fiber Raman amplifiers, with their advantages of low cost, low nonlinear distortion, almost infinite gain bandwidth, high output power saturation and simple construction compared with other systems, have become long distances. Ideal technology widely used in large capacity dense wavelength division multiplexing systems. Raman amplifiers take stimulated Raman scattering (SRS) as amplification principle, system optical fiber as amplification medium and high power short wavelength optical wave as pump to amplify the long wavelength and low power channel information light wave. When pumping amplifies the signal, it is not equal gain amplification, but is affected by many factors, so the optical fiber communication system should consider the flatness of the signal gain while amplifying the signal. The received power of the signal at the receiving end is generally stable. The main research points of this paper are as follows: first, based on the previous researches on Raman amplifiers, the principle and characteristics of Raman amplifiers are introduced based on the characteristics and applications of optical fiber Raman amplifiers (FRAs). The theoretical model of Raman amplifier is introduced to analyze the relationship between system gain and system parameters (signal initial power, pump power, fiber distance, etc.). Secondly, the noise of optical fiber communication system is deeply analyzed, the theoretical model of correlated noise is established, and the double Rayleigh backscattering noise is analyzed and studied in detail. The influence of noise on the system and the mathematical relationship between noise and system parameters are obtained. Thirdly, based on the transmission coupling equation of fiber Raman amplifier, the distribution of pump and signal power along the fiber is numerically analyzed, and the gain flatness of the amplification system is optimized by the improved particle swarm optimization algorithm. The system gain fluctuation is increased from 3dB to 0.5 dB.
【學(xué)位授予單位】：西安郵電大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TN722;TN929.11

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本文編號(hào)：2251029