液芯光子晶体光纤制备和锁模器件研究
发布时间：2018-11-19 22:03
【摘要】：液芯光纤以其很小的弯曲半径,良好的散热性,很高的掺杂浓度,被广泛应用于通信,医疗和传感等很多方面。近年来人们研究利用光子晶体光纤填充液体作为液芯光子晶体光纤的应用成为研究的热点。本文将利用光子晶体光纤填充溶液,研究光子晶体光纤的液体填充特性、填充制备、后端面处理和作为光纤锁模器件在激光器中的应用。本文主要研究工作围绕着:理论上,分析了空芯光子晶体光纤和双芯光纤填充的优势、填充溶液的方法。从原理方面对增益掺杂光子晶体光纤和锁模启动元件两部分进行了数学描述。其中对增益掺杂光子晶体光纤的描述包含其模式特性和传输特性两个方面。为液芯光子晶体光纤作为光纤锁模器件的理论和实验研究奠定了基础。首次提出把双液芯光子晶体光纤作为锁模启动元件的锁模激光器,进行了仿真模拟,基于双芯光子晶体光纤的非线性耦合特性,得到了输出脉冲的压缩。实现了在低功率下,从一个纤芯入射的功率在耦合作用下经过一个耦合长度后从相邻的纤芯输出;在高功率下,由于非线性作用改变了入射光纤的折射率,纤芯之间的相位失配增加,从一个纤芯入射的功率保持在这个纤芯中传输,满足可饱和吸收作用。仿真设计了腔型结构,把双液芯光子晶体光纤作为可饱和吸收体,模拟腔内动力学过程,得到稳定的锁模输出。分析研究了双芯光子晶体光纤非线性模式耦合和光纤长度对锁模的影响,得到了光纤长度与线性耦合长度不是整数倍,实现自启动和稳定的锁模,当光纤长度远大于线性耦合长度时,需要滤波器来稳定锁模运转。实验上,利用普通熔接机放电对光纤塌陷进行选择性填充,通过不同光子晶体光纤之间的塌陷对比得到放电塌陷参数,并对空芯光子晶体光纤和双芯光子晶体光纤进行了选择性填。利用虹吸法填充溶液,截断法观测纤芯液体填充是否均匀,最后对光纤端面进行后处理,如对填充后的光纤进行塌陷、研磨等,这大大增加了光纤端面的平整度,提高了耦合效率和出射光斑质量。为了对制备的液芯光子晶体光纤器件进行验证,把制备的液芯光纤进行空间光耦合输出,得到了很好光斑质量输出。综上,在理论和实验研究的基础上,有望进一步把制备的液芯光子晶体光纤作为光纤器件运用到探索可见光波段的放大器和振荡器,并得到光波段的拓展及锁模器件的广泛应用。
[Abstract]:Liquid core fiber has been widely used in many fields such as communication, medical treatment and sensing because of its small bending radius, good heat dissipation and high doping concentration. In recent years, the application of photonic crystal fiber filled liquid as liquid core photonic crystal fiber has become a hot topic. In this paper, the liquid filling characteristics of photonic crystal fiber (PCF), its preparation, back-end surface treatment and its application as fiber mode-locking devices are studied by using photonic crystal fiber filling solution. This paper focuses on: theoretically, the advantages of empty-core photonic crystal fiber and double-core fiber filling and the method of filling solution are analyzed. Two parts of gain doped photonic crystal fiber and mode-locked starter are described mathematically in principle. The description of gain doped photonic crystal fiber includes two aspects: mode characteristic and transmission characteristic. It lays a foundation for the theoretical and experimental study of liquid core photonic crystal fiber as an optical fiber mode-locking device. A mode-locked laser using dual-liquid core photonic crystal fiber as the mode-locking starting element is proposed for the first time. The output pulse compression is obtained based on the nonlinear coupling characteristics of the two-core photonic crystal fiber. Under low power, the incident power from one fiber core passes through a coupling length and then outputs from the adjacent core. At high power, the refractive index of the incident fiber is changed due to the nonlinear effect, and the phase mismatch between the cores increases. The incident power from one core is kept in the core to satisfy the saturable absorption effect. The cavity structure is simulated and the two-core photonic crystal fiber is used as the saturable absorber to simulate the dynamic process in the cavity and obtain a stable mode-locked output. The effects of nonlinear mode coupling and fiber length on mode-locking of two-core photonic crystal fiber are analyzed and studied. It is concluded that the length of fiber and linear coupling length are not integer times, so the self-starting and stable mode-locking can be realized. When the fiber length is much longer than the linear coupling length, a filter is needed to stabilize the mode-locked operation. In the experiment, the conventional welding machine is used to fill the fiber collapse selectively, and the discharge collapse parameters are obtained by comparing the collapse of different photonic crystal fibers. The empty core photonic crystal fiber and two core photonic crystal fiber were filled selectively. The siphon method is used to fill the solution, the truncation method is used to observe the uniformity of the liquid filling of the fiber core. Finally, the end surface of the fiber is post-treated, such as the collapse and grinding of the filled fiber, which greatly increases the smoothness of the fiber end surface. The coupling efficiency and the quality of the speckle are improved. In order to verify the fabricated liquid-core photonic crystal fiber devices, the liquid-core optical fiber is output by spatial light coupling, and a good light spot quality output is obtained. In summary, on the basis of theoretical and experimental research, it is expected that the liquid-core photonic crystal fiber will be further used as an optical fiber device to explore the visible light band amplifiers and oscillators. The expansion of optical wave band and the wide application of mode-locked devices are obtained.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253
，
本文编号：2343549
[Abstract]:Liquid core fiber has been widely used in many fields such as communication, medical treatment and sensing because of its small bending radius, good heat dissipation and high doping concentration. In recent years, the application of photonic crystal fiber filled liquid as liquid core photonic crystal fiber has become a hot topic. In this paper, the liquid filling characteristics of photonic crystal fiber (PCF), its preparation, back-end surface treatment and its application as fiber mode-locking devices are studied by using photonic crystal fiber filling solution. This paper focuses on: theoretically, the advantages of empty-core photonic crystal fiber and double-core fiber filling and the method of filling solution are analyzed. Two parts of gain doped photonic crystal fiber and mode-locked starter are described mathematically in principle. The description of gain doped photonic crystal fiber includes two aspects: mode characteristic and transmission characteristic. It lays a foundation for the theoretical and experimental study of liquid core photonic crystal fiber as an optical fiber mode-locking device. A mode-locked laser using dual-liquid core photonic crystal fiber as the mode-locking starting element is proposed for the first time. The output pulse compression is obtained based on the nonlinear coupling characteristics of the two-core photonic crystal fiber. Under low power, the incident power from one fiber core passes through a coupling length and then outputs from the adjacent core. At high power, the refractive index of the incident fiber is changed due to the nonlinear effect, and the phase mismatch between the cores increases. The incident power from one core is kept in the core to satisfy the saturable absorption effect. The cavity structure is simulated and the two-core photonic crystal fiber is used as the saturable absorber to simulate the dynamic process in the cavity and obtain a stable mode-locked output. The effects of nonlinear mode coupling and fiber length on mode-locking of two-core photonic crystal fiber are analyzed and studied. It is concluded that the length of fiber and linear coupling length are not integer times, so the self-starting and stable mode-locking can be realized. When the fiber length is much longer than the linear coupling length, a filter is needed to stabilize the mode-locked operation. In the experiment, the conventional welding machine is used to fill the fiber collapse selectively, and the discharge collapse parameters are obtained by comparing the collapse of different photonic crystal fibers. The empty core photonic crystal fiber and two core photonic crystal fiber were filled selectively. The siphon method is used to fill the solution, the truncation method is used to observe the uniformity of the liquid filling of the fiber core. Finally, the end surface of the fiber is post-treated, such as the collapse and grinding of the filled fiber, which greatly increases the smoothness of the fiber end surface. The coupling efficiency and the quality of the speckle are improved. In order to verify the fabricated liquid-core photonic crystal fiber devices, the liquid-core optical fiber is output by spatial light coupling, and a good light spot quality output is obtained. In summary, on the basis of theoretical and experimental research, it is expected that the liquid-core photonic crystal fiber will be further used as an optical fiber device to explore the visible light band amplifiers and oscillators. The expansion of optical wave band and the wide application of mode-locked devices are obtained.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN253
，
本文编号：2343549
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