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  本文選題：石墨烯　切入點：鎖模　出處：《山東大學(xué)》2015年碩士論文

【摘要】：摻鉺光纖激光器自上世紀八十年代誕生以來一直是光通信領(lǐng)域研究的熱點,其輸出特性經(jīng)歷了從連續(xù)運轉(zhuǎn)到單縱模輸出直至超快脈沖的產(chǎn)生等幾個階段,并在光纖通信、光纖傳感、生物醫(yī)療等領(lǐng)域發(fā)揮著越來越重要的作用。具有超快脈沖輸出特性的摻鉺光纖激光器因其脈沖持續(xù)時間極短和峰值功率極高等特點近年來逐漸成為研究的熱點。超快脈沖激光主要通過調(diào)Q和鎖模技術(shù)來實現(xiàn),其中被動鎖模技術(shù)能產(chǎn)生皮秒乃至飛秒量級的超快脈沖且其系統(tǒng)結(jié)構(gòu)簡單而備受青睞。被動鎖模是利用材料的非線性吸收或非線性相變的特性來產(chǎn)生激光超快脈沖,目前,比較成熟的非線性材料有半導(dǎo)體可飽和吸收鏡和碳納米管可飽和吸收體。但是制作半導(dǎo)體可飽和吸收鏡需要相對復(fù)雜和昂貴的超凈制造系統(tǒng),這類器件的典型恢復(fù)時間約為幾個納秒,且半導(dǎo)體可飽和吸收鏡的光損傷閾值很低,常用的半導(dǎo)體飽和吸收鏡吸收帶寬較窄。碳納米管是一種直接帶隙材料,帶隙大小由碳納米管直徑和屬性決定。不同直徑碳納米管的混合可以實現(xiàn)寬的非線性吸收帶,覆蓋常用的1.0-1.6μm激光增益發(fā)射波段。但是由于碳納米管的管狀形態(tài)會產(chǎn)生很大的散射損耗,提高了鎖模閾值,限制了激光輸出功率和效率。所以,研究人員一直在尋找一種具有高光損傷閾值、超快恢復(fù)時間、寬帶寬和價格便宜等優(yōu)點的飽和吸收材料。近年來研究者發(fā)現(xiàn)石墨烯由于它獨特的零帶隙結(jié)構(gòu),對所有波段的光都無選擇性的吸收,且具有超快的恢復(fù)時間和較高的損傷閾值。因此利用石墨烯獨特的非線性可飽和吸收特性將其制作成可飽和吸收體應(yīng)用于被動鎖模光纖激光器已經(jīng)成為超快脈沖激光器研究領(lǐng)域的熱點。本文正是基于將石墨烯可飽和吸收應(yīng)用于摻鉺光纖激光器來實現(xiàn)被動鎖模開展了理論和實驗研究,具體工作如下：簡單介紹了摻鉺光纖激光器的研究進展,對并摻鉺光纖放大器和摻鉺光纖激光器的理論基礎(chǔ)做了分析。實驗研究了摻鉺光纖激光器的輸出特性與泵浦源功率、增益光纖長度以及腔長等因素之間的對應(yīng)關(guān)系。利用摻鉺光纖熒光光源的光譜輸出特性,找到了實驗用摻鉺光纖激光器的最佳增益光纖長度。在此基礎(chǔ)上,介紹了光纖激光器的工作原理,開展了連續(xù)激光實驗,得到了穩(wěn)定的連續(xù)激光輸出。分析了超快脈沖產(chǎn)生的機理,介紹了調(diào)Q技術(shù)和鎖模技術(shù)實現(xiàn)超快脈沖輸出的理論依據(jù),同時對三種常見的可飽和吸收體,即半導(dǎo)體可飽和吸收鏡、碳納米管和石墨烯可飽和吸收體,從制作方法、制作成本、吸收帶寬、損傷閾值、恢復(fù)時間和調(diào)制深度等幾個方面的特性進行了對比。對石墨烯的能級結(jié)構(gòu)及其獨特的光電特性進行了系統(tǒng)的研究；分析了石墨烯的超快弛豫過程和可飽和吸收的相關(guān)機理；分析了石墨烯極低的電阻率的物理機制。利用化學(xué)氣相沉積法制備了高質(zhì)量的單層石墨烯薄膜并分別利用濕法和干法將石墨烯薄膜轉(zhuǎn)移到光纖跳線氧化鋯插芯的端面上,由于該過程是層數(shù)可控的,我們分別轉(zhuǎn)移了一層、兩層和六層到三個不同的光纖跳線氧化鋯插芯的端面上,制成了三種層數(shù)不同的石墨烯可飽和吸收體并對其可飽和吸收特性進行了實驗研究。實驗研究了基于不同參數(shù)石墨烯可飽和吸收體的摻鉺脈沖光纖激光器的光學(xué)輸出特性,得到了皮秒量級的鎖模輸出脈沖串。建立石墨烯可飽和吸收體參數(shù)與鎖模脈沖輸出之間的對應(yīng)關(guān)系,并對激光腔的參數(shù)進行了優(yōu)化。
[Abstract]:Erbium doped fiber laser has been a hot research topic in the field of optical communication since the last century, was born in 80s, the output characteristics of experience from the continuous operation to single longitudinal mode output until the ultrafast pulse generation in several stages, and in optical fiber communication, optical fiber sensing, biomedical and other fields play an increasingly important role. With fast the pulse output characteristics of erbium doped fiber laser because of its extremely short pulse duration and high peak power has gradually become the research hotspot in recent years. Mainly through regulating Q ultrafast pulsed laser and mode-locked technology to realize, which passively mode-locked technology can produce picosecond and femtosecond laser pulse and the system has the advantages of simple structure and favored passive mode locking is. The nonlinear absorption properties of materials or nonlinear by the phase transformation to produce laser ultrafast pulses, the nonlinear material of mature half The conductor saturable absorption mirror and carbon nanotubes SATURABLEABSORBER. But the production of semiconductor saturable absorption mirror requires relatively complicated and expensive ultra clean manufacturing system, typical of this kind of device recovery time is about several nanoseconds, and a semiconductor saturable absorber mirror optical damage threshold is very low, the commonly used semiconductor saturable absorber mirror with narrow absorption bandwidth. The carbon nanotube is a kind of direct band gap material, the band gap size by the diameters of carbon nanotubes and attribute decision. To achieve a wide nonlinear absorption band of carbon nanotube can be mixed with different diameters, covering 1.0-1.6 m laser used to gain emission band. But due to the tubular morphology of carbon nanotubes will produce large scattering loss, improve the mode locking threshold, limit the laser output power and efficiency. Therefore, researchers have been looking for a high optical damage threshold, ultrafast recovery time, bandwidth and price is Should the advantages of saturated absorption materials. In recent years, the researchers found that graphene due to its unique zero band gap structure of all bands of light selective absorption, and has a fast recovery time and high damage threshold. So the nonlinear graphene unique saturable absorption to produce a saturable the absorber used in passively mode-locked fiber laser has become the research focus in the field of ultrafast pulsed laser. This paper is based on the graphene saturable absorber used in erbium-doped fiber laser to realize passive mode-locked carried out theoretical and experimental research, the specific work is as follows: This paper introduces the research progress of erbium doped fiber laser, the based on theoretical analysis and erbium-doped fiber amplifier and erbium-doped fiber laser. Experimental study on the output characteristics and pump power erbium-doped fiber laser, gain fiber The relationship between length and cavity length and other factors. The spectral output characteristics of erbium-doped fiber, find the best gain fiber length of erbium doped fiber laser experiments. On this basis, introduces the working principle of the fiber laser, the CW laser experiment, obtained the continuous stable output analysis. The mechanism of ultrafast pulse generation, introduces Q technology and mode locking technology to achieve ultra fast pulse output theory, at the same time, three kinds of saturable absorber, namely SESAM, carbon nanotubes and graphene saturable absorber, from the production method, production cost, absorption bandwidth, damage threshold compared the recovery time and the modulation depth of the characteristics of several aspects. The energy level structure of graphene and its unique optoelectronic properties were studied; the analysis of ultrafast graphene The relaxation process and mechanism of saturable absorption; analysis of the physical mechanism of low resistivity graphene. By chemical vapor deposition of the graphene film of high quality and are using wet and dry graphene film transfer to zirconia fiber jumper ferrule end face, because this process is the number of controllable, we transfer a layer, surface layer and the six layer two to three different optical fiber jumper zirconia core insert on graphene layers made of three kinds of different saturable absorber and the saturable absorption properties were experimentally studied. Experimental study on the optical output characteristics of erbium doped the different parameters of the graphene saturable absorber pulse fiber laser based on the mode-locked output pulse on picosecond. Establish the corresponding relationship between the graphene can be saturated absorber parameters and mode-locked pulse output The parameters of the laser cavity are optimized.

【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN248

【參考文獻】

相關(guān)期刊論文 前1條

1 任文才;高力波;馬來鵬;成會明;;石墨烯的化學(xué)氣相沉積法制備[J];新型炭材料;2011年01期

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本文編號：1662097