本文選題：激光直寫　切入點：光纖微透鏡　出處：《浙江大學》2015年碩士論文　論文類型：學位論文

【摘要】：激光二極管具有體積小、重量輕、價格便宜等優(yōu)勢,在光纖通信、生物醫(yī)學、激光泵浦、材料加工等領(lǐng)域被廣泛應(yīng)用。在許多應(yīng)用場合都需要將激光二極管與光纖進行耦合,然而激光二極管由于其發(fā)光面較寬,其出射光束為橢圓形模場,這與光纖的圓形模場不匹配,因此兩者直接的耦合效率很低。為了提高激光二極管與光纖的耦合效率,一種常用的方法是在光纖端面上制作微透鏡,與激光二極管直接耦合。盡管目前已有如熔融拉伸法、化學蝕刻法、研磨拋光法等一些制作光纖微透鏡的方法,但這些方法或多或少存在著制作過程復(fù)雜,耗費時間長,加工成本高等缺點。因此本文提出激光直寫法制作光纖微透鏡,該方法能夠直接在光纖端面上打印出微透鏡,操作過程簡單方便、快速、成本低、可重復(fù)性高。本文采用激光直寫法制作出不同形狀的光纖微透鏡,并對它們的耦合效率進行了測試。測試采用650nm波長的激光二極管,其水平發(fā)散角為6.50,垂直發(fā)散角為35°,橢圓光束的長寬比為5。用該激光二極管與制作的光纖微透鏡進行耦合,測試耦合效率,實驗中獲得的最高耦合效率為53.5%。耦合效率與光纖微透鏡的形狀有關(guān)。將光纖微透鏡尖端的曲率半徑定義為其最小內(nèi)切圓的半徑,當內(nèi)切圓的半徑為8.1μm時,具有最高的耦合效率。光纖微透鏡的高度與其曲率半徑成反比,耦合效率最高時,光纖微透鏡的高度為50μm,容差為+5/-0μm。將光纖微透鏡頂點與激光二極管發(fā)光面之間的距離定義為光纖微透鏡的工作距離,則耦合效率與工作距離有關(guān)。實驗中獲得,當工作距離為15.8μm時,耦合效率最高。光纖微透鏡與激光二極管存在軸向位移(水平或垂直)、角向傾斜(水平或垂直)時,其耦合效率下降。實驗測得,耦合損耗增加1dB,X軸、Y軸兩個方向偏移位移的容忍誤差分別為±2.5μm、±1.2μm,水平傾斜角和垂直傾斜角的容忍誤差分別為±2.0°、±5.0°。本文在ZEMAX軟件中采用光線追跡法對光纖微透鏡與激光二極管的耦合進行了仿真,仿真結(jié)果與實驗結(jié)果一致。
[Abstract]:Laser diodes are widely used in optical fiber communication, biomedicine, laser pump, material processing and other fields because of their advantages of small size, light weight, low price and so on. However, due to the wide luminescence surface of laser diode, the output beam of laser diode is elliptical mode field, which does not match the circular mode field of optical fiber, so the direct coupling efficiency of both laser diode and fiber is very low, in order to improve the coupling efficiency between laser diode and fiber, One commonly used method is to make microlenses on the end of the fiber, which are directly coupled to laser diodes. Although there are some methods for making optical fiber microlenses, such as melt drawing, chemical etching, grinding and polishing, etc. However, these methods have the disadvantages of complicated fabrication process, long time consumption, high processing cost, etc. In this paper, a laser direct writing method is proposed to fabricate optical fiber microlens, which can print out the microlens directly on the end surface of the optical fiber. The operation process is simple and convenient, fast, low cost and high repeatability. In this paper, optical fiber microlenses with different shapes have been fabricated by laser direct-writing, and their coupling efficiency has been tested. The horizontal divergence angle is 6.50, the vertical divergence angle is 35 擄, and the aspect ratio of the elliptical beam is 5. The coupling efficiency is measured by coupling the laser diode with the fabricated fiber microlens. The maximum coupling efficiency obtained in the experiment is 53.5. The coupling efficiency is related to the shape of the fiber microlens. The radius of curvature at the tip of the optical fiber microlens is defined as the radius of its minimum inner tangent circle. When the radius of the inner tangent circle is 8.1 渭 m, Has the highest coupling efficiency. The height of the optical fiber microlens is inversely proportional to its curvature radius, when the coupling efficiency is highest, The height of the optical fiber microlens is 50 渭 m and the tolerance is 5 / -0 渭 m. If the distance between the top of the fiber microlens and the luminescent surface of the laser diode is defined as the working distance of the optical fiber microlens, the coupling efficiency is related to the working distance. When the working distance is 15.8 渭 m, the coupling efficiency is the highest. When there is axial displacement (horizontal or vertical) between the optical fiber microlens and the laser diode, the coupling efficiency decreases when the angle tilts (horizontal or vertical). The tolerance error of offset displacement of X axis and Y axis is 鹵2.5 渭 m and 鹵1.2 渭 m respectively, and the tolerance error of horizontal and vertical tilt angle is 鹵2.0 擄and 鹵5.0 擄respectively. In this paper, the ray tracing method is used to trace the optical fiber microlens and laser in ZEMAX software. The coupling of the diode is simulated. The simulation results are in agreement with the experimental results.
【學位授予單位】：浙江大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN31

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本文編號：1610261