摘要：为了进一步提高掺铥( Tm )光纤激光器的连续波输出功率，根据一般掺Tm双包层光纤激光器46%的斜效率( 输出功率很低 )，泵浦源的功率就需要提高到两倍于输出功率的水平。我们使用合束器对三个半导体激光器进行合束来提高总的输入功率，在增益光纤两端使用反射率分别为10%及98%的光纤光栅( FBG )作为谐振腔镜，并对合束器的信号尾纤以及激光输出尾纤进行8°斜角切割以抑制宽带反馈。由于掺铥激光器为三能级系统，这种能级系统使得激光器在低温下才能获得较高的效率；并且在高功率条件下由793 nm泵浦波长产生2 μm激光波长造成的量子亏损热逐渐积累，当温度过高会造成光纤涂覆层损伤 ( 正常工作温度一般低于80℃ )，甚至造成光纤熔丝损伤，在实验中使冷却水温保持在10℃以对光纤进行有效散热。基于该实验装置，利用长度为2.5 m的掺Tm增益光纤，获得了最高达到46.4 W的连续输出功率，激光波长为1907 nm，对应于耦合泵浦功率的斜率效率达到36.3%。

该论文有8幅，参考文献16篇。

关键词：掺铥激光器；全光纤；高功率

The Experimental Research of High Power All-Fiber Tm Doped Fiber Laser

Abstract：In order to realize the high-power operation of the Tm doped silica fiber laser， we need to use higher-power pump sources which should be twice of the output power due to the slope efficiency of 46% . Three semiconductor laser are combined by a beam combiner to improve the input power. To prevent feedback , we have a 8°cutting directly of the passive fiber and gain fiber., then weld them together and sealing glue. Using FBG( Fiber Brag Grating )which reflex angle are 10°and 90° respectively take the place of prism to produce laser.  Since the pump light can not be confined in inner-cladding completely. The escaped pump light beats the fluorinated polymer coating directly and the beat combined with the thermal loading from quantum defect heating in the core may damage the coating ( with a low withstand temperatures up to 80℃)，even ignited the coating and the fused the silica fiber, so we can only use water cooled heat sinks but not design beam shaping which can improve the beam quality to get a higher output power. Based on this configuration a continuous-wave output power of up to 46.4W operating at 1907 nm was obtained for 2.5 m-long gain fiber, corresponding to a slope efficiency of 36.3% with respect to the launched pump power. The results indicate that if coupling pump laser by welding the fiber end together, using beam combiner to get higher pump power can lead a higher output power when the gain fiber is under the low withstand temperature. This paper include 8 pictures and 16 references.

Key Words: Tm Doped Laser  FBG   All-Fiber  High Power

目录

摘要 I

Abstract II

1 绪论 1

1.1激光及激光器概述 1

1.2选题背景 1

1.3 国内外研究现状 3

1.4本文主要研究内容 4

1.5本文主要创新点 4

2 光纤激光器的构成 5

2.1 泵浦源 5

2.2 增益介质 6

2.3 谐振腔 7

3 实验部分 9

3.1实验操作 9

3.1.1泵浦源的选取 9

3.1.2 增益光纤长度选取 10

3.1.1 实验准备 10

3.1.4实验注意事项 11

3.2实验结果 11

4 结论 14

参考文献 15

1 绪论

1.1激光及激光器概述

自然界中普通的光通过自发辐射而产生，而“激光( Laser )”是受激辐射对光放大( Light amplification by stimulated emission of radiation )的简称[1]。1917年，爱因斯坦以光量子假设为基础，提出了两种发光形式的概念，即光具有自发辐射和受激辐射情况，从理论上证明了受激辐射光存在的可能性。20世纪五十年代，科研工作者在实验上实现粒子数反转，从而预见了受激辐射光放大器的诞生。同期美国科学家Townes发明一种低噪声微波波段受激辐射放大器( Maser )。随后他们于1958年提出此种放大器原理在特定条件下可以推广到光波波段，从而制成制成受激辐射光放大器。1960年7月美国科学家Maiman Y H成功研制出世界上首台红宝石脉冲固体激光器[2]，这是人类历史上首次成功的制造出激光，激光与自然光相比具有单色性高、相干性强、方向性好、高亮度以及高光子简并度的特性，以其特殊的性质以及用途引起人们广泛关注[3]。