發(fā)布時(shí)間：2018-06-13 14:37

  本文選題：外腔半導(dǎo)體激光器 + 液晶相位延遲器�。� 參考：《中國科學(xué)院研究生院(國家授時(shí)中心)》2012年博士論文

【摘要】：時(shí)間頻率是一個(gè)國家科技、經(jīng)濟(jì)、軍事和社會(huì)生活中至關(guān)重要的參量，其應(yīng)用范圍從基礎(chǔ)研究（相對論驗(yàn)證、基本物理常數(shù)測量等），滲透到了工程技術(shù)應(yīng)用領(lǐng)域（導(dǎo)航定位、深空探測等）。標(biāo)準(zhǔn)時(shí)間首先由一組連續(xù)運(yùn)行的守時(shí)型原子鐘（如商品型銫束原子鐘、氫原子鐘）產(chǎn)生穩(wěn)定的信號(hào)，經(jīng)過基準(zhǔn)型原子鐘（如銫原子噴泉鐘、實(shí)驗(yàn)室型銫束原子鐘）校準(zhǔn)后獲得穩(wěn)定、準(zhǔn)確的時(shí)間信號(hào)。銫原子噴泉鐘作為基準(zhǔn)鐘標(biāo)較著其他原子鐘，具有最高的準(zhǔn)確度性能和優(yōu)異的長期穩(wěn)定度性能。相比于現(xiàn)有的守時(shí)原子鐘，銫原子噴泉鐘不存在氫鐘所固有的頻率漂移，比商品型銫束原子鐘具有更高的頻率穩(wěn)定度（1個(gè)量級以上），參與守時(shí)能夠顯著提高時(shí)間頻率信號(hào)的長期穩(wěn)定度性能。 然而，銫原子噴泉鐘作為守時(shí)鐘運(yùn)行仍然需要解決以下兩個(gè)關(guān)鍵問題：一是銫原子噴泉鐘的可靠性問題。目前作為基準(zhǔn)鐘運(yùn)行的銫原子噴泉運(yùn)行是間歇性的，而作為守時(shí)鐘運(yùn)行則要求輸出信號(hào)是連續(xù)的，以保證時(shí)間信號(hào)的持續(xù)性。銫原子噴泉鐘是大型的實(shí)驗(yàn)室裝置，各種環(huán)境因素（機(jī)械振動(dòng)等）的干擾容易導(dǎo)致噴泉鐘偏離正常的工作狀態(tài)，研究能夠自動(dòng)恢復(fù)工作狀態(tài)的技術(shù)能夠是其中需要研究的關(guān)鍵技術(shù)之一；二是需要解決銫原子噴泉準(zhǔn)確度和穩(wěn)定度性能相互矛盾的問題。銫原子噴泉鐘作為守時(shí)鐘運(yùn)行在保證高準(zhǔn)確度的同時(shí)也必須具有高的穩(wěn)定度性能。當(dāng)噴泉鐘原子樣品數(shù)目越小時(shí)，原子樣品之間的碰撞程度減弱，導(dǎo)致的碰撞頻移誤差減小，如此一來穩(wěn)定度性能指標(biāo)就響應(yīng)地降低。研究能夠同時(shí)提高準(zhǔn)確度性能和穩(wěn)定度性能的技術(shù)是另一項(xiàng)需要研究的關(guān)鍵技術(shù)。 本文圍繞上述問題開展研究，首先研制了具有抗振特性的外腔半導(dǎo)體激光器，在此基礎(chǔ)上，研究了具有參數(shù)自恢復(fù)激光穩(wěn)頻技術(shù)，解決了限制銫原子噴泉鐘連續(xù)運(yùn)行能力的主要問題；研究了能夠獲得低密度原子樣品同時(shí)又能保證原子團(tuán)數(shù)目不變的慢速原子束技術(shù)，可同時(shí)提高銫噴泉鐘準(zhǔn)確度和穩(wěn)定度性能指標(biāo)。在實(shí)現(xiàn)的關(guān)鍵技術(shù)基礎(chǔ)上，研制了銫原子噴泉鐘的其中兩個(gè)子系統(tǒng)物理系統(tǒng)、光學(xué)系統(tǒng)，通過整機(jī)聯(lián)調(diào)，獲得了銫原子噴泉鐘的標(biāo)志性Ramsey信號(hào)，實(shí)現(xiàn)了初步閉環(huán)，研究內(nèi)容和成果可歸納為以下幾個(gè)部分： （1）研制了應(yīng)用干涉濾光片選模，具有“貓眼”結(jié)構(gòu)和參數(shù)自恢復(fù)鎖頻功能的新型852nm抗振外腔半導(dǎo)體激光器系統(tǒng)，并成功應(yīng)用于銫原子噴泉鐘裝置。分析研究了基于干涉濾光片選模、“貓眼”結(jié)構(gòu)外腔壓窄線寬的外腔激光器的工作原理，與基于光柵選模、FP腔壓窄線寬的外腔激光器對比，分析了研制的外腔半導(dǎo)體激光器的抗振特性。測試了抗振外腔半導(dǎo)體激光器的頻譜特性，與同類的外腔半導(dǎo)體激光器相比，研制的激光器具有更窄的線寬和更高的頻譜純度。 （2）首次實(shí)現(xiàn)了基于液晶相位可變延遲器頻率調(diào)諧、“貓眼”結(jié)構(gòu)外腔的半導(dǎo)體激光器，提出了基于半導(dǎo)體光放大芯片新型外腔半導(dǎo)體激光器方案。針對PZT頻率調(diào)諧的外腔半導(dǎo)體激光器固有的回程誤差、機(jī)械運(yùn)動(dòng)和驅(qū)動(dòng)電壓高等缺點(diǎn)，采用了以液晶相位延時(shí)器進(jìn)行調(diào)諧的方案。在此基礎(chǔ)上，實(shí)現(xiàn)了液晶調(diào)諧的外腔半導(dǎo)體激光器。測試表明，研制的激光器具有調(diào)諧電壓低，不存在回程誤差和機(jī)械運(yùn)動(dòng)等優(yōu)點(diǎn)。 （3）研究了2D MOT慢速原子束技術(shù)。通過構(gòu)建了2D MOT中銫原子的受力模型，對2D MOT產(chǎn)生慢速原子束的過程進(jìn)行了數(shù)值模擬。利用模擬結(jié)果，設(shè)計(jì)并實(shí)現(xiàn)了完整的慢速原子束裝置，利用飛行時(shí)間法測試了慢速原子束的流量、平均速度等特性，獲得了性能指標(biāo)較好的慢速原子束。采用慢速原子束直接通過光學(xué)粘團(tuán)制備原子樣品，可以縮短裝載時(shí)間，降低原子團(tuán)密度，同時(shí)提高頻率穩(wěn)定度性能和準(zhǔn)確度性能。 （4）研制了銫原子噴泉鐘的物理系統(tǒng)和光學(xué)系統(tǒng)，，通過整機(jī)聯(lián)調(diào)，成功地獲得了銫原子噴泉鐘的標(biāo)志性信號(hào)---Ramsey條紋，并初步實(shí)現(xiàn)了噴泉鐘的閉環(huán)運(yùn)行。在研制的抗振外腔半導(dǎo)體激光器的基礎(chǔ)上，通過飽和吸收光譜，實(shí)現(xiàn)了激光器的自動(dòng)穩(wěn)頻，并利用聲光調(diào)制器實(shí)現(xiàn)了激光頻率、功率控制，通過光放大、注入鎖定方法實(shí)現(xiàn)光功率放大。通過保偏光纖把激光傳輸?shù)揭惑w化鏡筒，擴(kuò)束形成準(zhǔn)直度高、功率和偏振可調(diào)的圓偏振光。構(gòu)建了斜入射激光探測光路，減小了熱原子熒光的干擾。全面分析了銫原子噴泉鐘對物理的要求，對物理系統(tǒng)進(jìn)行了方案設(shè)計(jì)。依據(jù)設(shè)計(jì)方案，實(shí)現(xiàn)了銫原子噴泉鐘的MOT阱區(qū)、探測區(qū)、噴泉管，達(dá)到了噴泉鐘運(yùn)行所需的指標(biāo)。在銫原子噴泉鐘光學(xué)系統(tǒng)、物理系統(tǒng)完成的基礎(chǔ)上，通過整機(jī)聯(lián)調(diào)，實(shí)現(xiàn)了銫原子的多普勒冷卻、上拋、偏振梯度冷卻，實(shí)現(xiàn)了原子噴泉。利用選態(tài)腔和推斥光，實(shí)現(xiàn)了mF=0態(tài)原子的選擇。通過在微波腔饋入微波，獲得了銫原子噴泉鐘的標(biāo)志性的Ramsey諧振信號(hào)。通過對微波信號(hào)實(shí)施方波調(diào)制，獲得了本地振蕩器的伺服控制信號(hào)，實(shí)現(xiàn)了噴泉鐘的初步閉環(huán)。
[Abstract]:Time and frequency is a vital parameter in a country's scientific, economic, military and social life. Its application ranges from basic research (relativistic verification, basic physical constant measurement, etc.) to the application field of Engineering (navigation and positioning, deep space exploration, etc.). The standard time is first run by a group of continuous time conservative atomic clocks (such as quotient). The caesium atomic clocks, hydrogen atomic clocks produce stable signals. After calibrating the standard atomic clocks (such as cesium fountain clocks, laboratory caesium beam atomic clocks), the stable and accurate time signals are obtained. The cesium fountain clock has the highest accuracy performance and excellent long-term stability performance as the reference clock is compared with the other atomic clocks. Compared with the existing time-saving atomic clocks, the cesium fountain clock does not have the frequency drift inherent to the hydrogen clock, which has a higher frequency stability than the commercial cesium beam atomic clock (1 orders of magnitude), and the time and frequency signal can significantly improve the long-term stability performance of the time frequency signal.
However, the cesium fountain clock still needs to solve the following two key problems: first, the reliability of the cesium fountain clock. The current operation of the cesium fountain as the reference clock is intermittent, and the output signal is continuous as a clock keeping operation in order to ensure the continuity of the time signal. The sub fountain clock is a large laboratory device. The interference of various environmental factors (mechanical vibration, etc.) may cause the fountain clock to deviate from the normal working state. It is one of the key technologies to study the technology that can automatically restore the working state. Two it is necessary to solve the mutual spear of the accuracy and stability of the cesium fountain. The caesium atomic fountain clock, as a clock guard, must have high accuracy as well as high stability. When the number of atomic clocks is smaller, the degree of collisions between the atomic samples decreases and the collision frequency shift error decreases. At the same time, improving the accuracy and stability performance is another key technology that needs to be studied.
In this paper, an external cavity semiconductor laser with anti vibration characteristics is first developed. On this basis, the parameter self recovery laser frequency stabilization technology is studied, and the main problem to restrict the continuous operation of cesium fountain clock is solved, and the low density atomic sample can be obtained and the atom can be guaranteed at the same time. The low speed atomic beam technique can simultaneously improve the accuracy and stability of the cesium fountain clock. On the basis of the key technology realized, two subsystems of the cesium fountain clock are developed, and the optical system is used to obtain the symbolic Ramsey signal of the cesium fountain clock. The research contents and achievements can be summarized as follows:
(1) a new type of 852nm anti vibration external cavity semiconductor laser system with "cat's eye" structure and self recovery of parameters has been developed, and it has been successfully applied to the cesium fountain clock device. The working origin of the external cavity laser based on interference filter selection mode and the narrow line width of the outer cavity of the cat eye structure is analyzed and studied. Compared with the external cavity laser based on the grating selection and the narrow line width of the FP cavity, the anti vibration characteristics of the developed external cavity semiconductor laser are analyzed. The spectrum characteristics of the anti vibration external cavity semiconductor laser are tested. Compared with the same kind of external cavity semiconductor laser, the laser apparatus has a narrower line width and higher spectral purity.
(2) a semiconductor laser based on the frequency tuning of the liquid crystal phase variable retarder and the outer cavity of the cat's eye is first realized. A novel external cavity semiconductor laser based on the semiconductor optical amplifier chip is proposed. The shortcomings of the inherent back range error of the PZT frequency tuning external cavity semiconductor laser, the high mechanical motion and the high driving voltage are adopted. On the basis of this, the liquid crystal tunable external cavity semiconductor laser is realized. The test shows that the laser has the advantages of low tuning voltage, no return error and mechanical motion.
(3) the 2D MOT slow atomic beam technique is studied. Through the construction of the force model of the cesium atom in 2D MOT, the process of the slow atomic beam produced by 2D MOT is simulated. The complete slow atomic beam device is designed and realized by the simulation results. The flow of the slow atomic beam and the average velocity are measured by the time of flight method. The slow atomic beam with good performance index is obtained. Using the slow atomic beam to prepare the atomic sample directly through the optical visco, it can shorten the loading time, reduce the density of the atomic mass, and improve the performance and accuracy of the frequency stability.
(4) the physical and optical systems of the cesium fountain clock have been developed. The ---Ramsey stripe of the caesium atomic fountain clock is successfully obtained through the adjustment of the whole machine, and the closed loop operation of the fountain clock is preliminarily realized. On the basis of the developed anti vibration external cavity semiconductor laser, the laser is realized by the saturated absorption spectrum. The laser frequency and power control are realized by the acousto-optic modulator. The optical power amplification is realized by the optical amplification and injection locking. The laser is transmitted to the integrated lens by the polarization maintaining fiber and the beam is expanded to form the circular polarized light with high collimation, power and polarization adjustable. The laser detection path of oblique incidence is constructed and the thermal atomic fluorescence is reduced. The requirements of the caesium fountain clock for physics are comprehensively analyzed and the physical system is designed. According to the design scheme, the MOT well area of the cesium fountain clock, the detection area and the fountain tube have been realized, and the requirements for the fountain clock operation are achieved. On the basis of the cesium atomic fountain clock optical system and the physical system completion, the whole machine is completed. In combination, the atomic fountain is realized by the Doppler cooling, throwing, and polarization gradient cooling of the cesium atom. The selection of the mF=0 state atom is realized by using the selected state cavity and the repulsion light. By feeding the microwave in the microwave cavity, the Ramsey resonant signal of the cesium fountain clock is obtained. The local wave modulation of the microwave signal is obtained. The servo control signal of the oscillator realizes the preliminary closed loop of the fountain clock.
【學(xué)位授予單位】：中國科學(xué)院研究生院(國家授時(shí)中心)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2012
【分類號(hào)】：P127.12

【引證文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

1 高峰;鍶光鐘的原子冷卻及互組躍遷譜線測量[D];中國科學(xué)院研究生院（國家授時(shí)中心）;2014年

本文編號(hào)：2014354