本文選題：摻銩光纖激光器 + 非線性放大環(huán)形鏡��； 參考：《深圳大學(xué)》2015年碩士論文

【摘要】：摻銩光纖具有極其豐富的熒光光譜,采用不同的泵浦技術(shù),可以獲得1650 nm至2150 nm的長波長激光輸出。而中心波長位于2μm附近的激光正處于水分子的紅外吸收峰,在外科手術(shù)或眼部的治療上都有著卓越的表現(xiàn)。同時,2μm激光在非線性頻率轉(zhuǎn)換、超低損耗長距離通信、工業(yè)制造等應(yīng)用領(lǐng)域都有著巨大的潛力。本文對基于非線性放大環(huán)形鏡(nonlinear amplified loop mirror,NALM)的全光纖被動鎖模摻銩激光器進(jìn)行了實驗研究。其中包括對激光器運行在全反常色散環(huán)境下的孤子動力模式和運行在凈正常色散環(huán)境下的耗散孤子共振的研究。具體內(nèi)容如下:(1)搭建了諧振腔長度為116 m的基于NALM的全光纖被動鎖模摻銩激光器,諧振腔在2μm波長范圍表現(xiàn)為全反常色散。當(dāng)泵浦功率超過鎖模閾值時,穩(wěn)定的鎖模狀態(tài)被輕易觸發(fā),重復(fù)頻率為1.72 MHz。在基頻鎖模下,激光器輸出的孤子鎖模脈沖中心波長位于1965.67 nm,并存在凱利邊帶。適當(dāng)調(diào)節(jié)偏振控制器,凱利邊帶消失,光譜變得平滑,半高全寬增加,此時激光器輸出類噪聲鎖模脈沖。增大泵浦功率,進(jìn)一步調(diào)節(jié)偏振控制器,鎖模脈沖變得不穩(wěn)定并開始分裂,最終形成了孤子雨。在觸發(fā)孤子雨狀態(tài)之后,繼續(xù)調(diào)節(jié)腔內(nèi)偏振態(tài),一種反孤子雨現(xiàn)象——孤子釋放被觀察到。進(jìn)一步調(diào)節(jié)腔內(nèi)偏振態(tài),流動光孤子的數(shù)量逐漸減少并最終消失,此時激光器輸出一種高能量的類矩形脈沖。隨著泵浦光功率的增加,它的最大脈寬和脈沖能量分別可達(dá)33 ns和37.7 n J。在增大泵浦功率的過程中,類矩形脈沖始終保持著單脈沖運轉(zhuǎn)。(2)搭建了諧振腔長度為64.3 m的基于NALM的全光纖被動鎖模摻銩激光器,引入了超高數(shù)值孔徑光纖作為色散補償元件,諧振腔在2μm波長范圍表現(xiàn)為凈正常色散,總色散量為+0.8585 ps~2@1900 nm。當(dāng)泵浦功率超過鎖模閾值時,穩(wěn)定的鎖模狀態(tài)被輕易觸發(fā),重復(fù)頻率為3.11 MHz。在基頻鎖模下,激光器輸出中心波長位于1941.08 nm,脈沖寬度為1.39 ns的矩形脈沖,其平均輸出功率為11.8 m W,對應(yīng)的單脈沖能量為3.79 n J。當(dāng)諧振腔滿足耗散孤子共振條件時,隨著泵浦光功率的增加,矩形脈沖持續(xù)加寬,其最大脈沖寬度和脈沖能量分別為6.19 ns和19.5 n J,峰值功率被鉗制在3.15 W附近。此外,通過適當(dāng)調(diào)節(jié)偏振控制器,矩形脈沖的中心波長可以從1940.22 nm被調(diào)節(jié)到1969.17 nm,存在28.95nm的波長可調(diào)諧范圍。
[Abstract]:Thulium doped fiber has abundant fluorescence spectra, and the long wavelength laser output from 1650 nm to 2150 nm can be obtained by using different pumping techniques. The laser with a central wavelength of about 2 渭 m is at the infrared absorption peak of water molecules and has excellent performance in surgery or eye treatment. At the same time, 2 渭 m laser has great potential in nonlinear frequency conversion, ultralow loss long distance communication, industrial manufacturing and so on. An all-fiber passively mode-locked thulium doped thulium laser based on nonlinear amplified loop mirror is studied experimentally in this paper. This includes the study of the dynamic mode of the soliton operating in the fully anomalous dispersion environment and the resonance of the dissipative soliton operating in the net normal dispersion environment. The main contents are as follows: 1) an all-fiber passively mode-locked thulium doped laser with a length of 116m is built based on NALM. The resonator exhibits all anomalous dispersion in the wavelength range of 2 渭 m. When the pump power exceeds the mode-locking threshold, the stable mode-locked state is easily triggered, and the repetition rate is 1.72 MHz. The center wavelength of the soliton mode-locked pulse is located at 1965.67 nm and there is a Kelly sideband under the fundamental frequency mode-locking. When the polarization controller is adjusted properly, the Kelly sideband disappears, the spectrum becomes smooth and the full width of the half-height increases, and the laser outputs a noise-like mode-locked pulse. When the pump power is increased and the polarization controller is further adjusted, the mode-locked pulse becomes unstable and begins to split, resulting in the formation of soliton rain. After triggering the state of the soliton rain, the polarization state in the cavity continues to be adjusted, and an anti-soliton rain phenomenon is observed-the release of the soliton is observed. Further adjusting the polarization state in the cavity, the number of mobile solitons gradually decreases and finally disappears. At this time, the laser outputs a kind of high-energy rectangular pulse. With the increase of pump power, the maximum pulse width and pulse energy can reach 33 ns and 37.7 n J, respectively. In the process of increasing pump power, the quasi-rectangular pulse always keeps the single pulse running. (2) an all-fiber passively mode-locked thulium doped laser based on NALM with cavity length of 64.3 m is built, and ultra-high numerical aperture fiber is introduced as dispersion compensation element. The resonator exhibits a net normal dispersion in the wavelength range of 2 渭 m, with a total dispersion of 0.8585 ps~2@1900 nm. When the pump power exceeds the mode-locking threshold, the stable mode-locked state is easily triggered, and the repetition rate is 3.11 MHz. The output center wavelength of the laser is 1941.08 nm and the pulse width is 1.39ns. The average output power is 11.8mW and the corresponding single pulse energy is 3.79nJ. When the cavity satisfies the dissipative soliton resonance condition, the rectangular pulse continues to widen with the increase of pump power. The maximum pulse width and pulse energy are 6.19 ns and 19.5nJ, respectively, and the peak power is clamped at 3.15 W. In addition, by properly adjusting the polarization controller, the center wavelength of the rectangular pulse can be adjusted from 1940.22 nm to 1969.17 nm, and there exists a tunable wavelength range of 28.95nm.
【學(xué)位授予單位】：深圳大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN248

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 殷科;楊未強;張斌;呂信明;侯靜;;高能量全光纖2μm摻銩脈沖光纖激光器[J];強激光與粒子束;2013年07期

2 殷科;楊未強;張斌;周航;侯靜;;10kW峰值功率高脈沖能量全光纖結(jié)構(gòu)2μm摻銩光纖激光器[J];強激光與粒子束;2014年01期

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