基于光纤光栅的外腔窄线宽半导体激光器

	基于光纤光栅的外腔窄线宽半导体激光器
其他题名	Narrow Linewidth External Cavity SemiconductorLaser Based on Fiber Bragg Grating
	刘大鹏
学位类型	硕士
导师	秦莉
	2015-11
学位授予单位	中国科学院大学
学位专业	凝聚态物理
关键词	外腔窄线宽半导体激光器光纤光栅有效反射率
摘要	光通信、光探测等领域的发展需要其核心元件—激光器拥有窄的线宽。现有窄线宽激光器如固体激光器等价格较为昂贵。而外腔激光器正是以其低廉的价格和优越的性能受到了人们的广泛关注。针对通信、探测、传感领域对线宽 <10kHz 半导体激光器的需求，本论文对基于光纤光栅的外腔半导体激光器进行了研究，包括光纤光栅外腔半导体激光器的结构优化、半导体激光增益芯片的研制、半导体激光增益芯片与光纤光栅的高效耦合以及光纤光栅外腔半导体激光器的性能分析等。在理论研究部分，本文创新性地将动态理论和静态理论结合，利用MATLAB，以等效腔模型和利用修正后的速率方程对外腔半导体激光器的静态特性—阈值和动态特性—线宽进行了模拟分析。模拟结果表明：该模型中激光器工作在60mA 时，外腔光栅反射率由0.1 提高至0.9 时，阈值电流从9.04mA 降低至4.01mA，线宽由95.27kHz 降低至1.34kHz；外腔长度由2cm 增加至6cm 时，激光器线宽由3.20kHz 降低至0.36kHz；增益芯片长度由600μm 降低至200μm 时，激光器线宽由1.69kHz 降低至1.22kHz。也就是说，外腔反馈的增强可以使激光器阈值和激线宽减小。外腔长度的增加可以在一定范围内有效压窄激光器线宽。增益芯片尺寸的减小也能对线宽压窄做出贡献。在实验部分，器件制作可分为三步，首先为1550nm 波段的InP 增益芯片的制作，然后为光纤外腔与波导外腔，经筛选后最终进行耦合封装。其难点在于要保证激光器的单模操作、保证足够大的耦合效率和稳定的工作条件。为保证单模操作，我们制备了性能优良的外腔反馈光栅（反射峰宽约50pm）。为保证足够的耦合效率，我们采用了透镜进行光束整形。为保证稳定的工作条件，我们使用了高精度的电流源和温度控制器TEC。最终经测量，该激光器的阈值电流约为12.37mA，最低线宽100.281Hz，国际上William 等人制作的类似结构的外腔激光器线宽为1kHz。
其他摘要	Narrow line-width laser is the core element of optical communications, optical detection and other areas. Existing narrow linewidth lasers such as solid-state lasers are quite expensive. In this condition, the external cavity lasers have gotten widely attention because of their low prices and superior performance. In order to fulfil the needs of optical communication, optical detection field, we set a goal of 10 kHz. Some research has been done in this article including simulation, device process and so on. As for the theory, an innovative way to simulate combined static theory and dynamic theory is presented. The static characteristic is simulated by MATLAB according to a brief model which use the effective reflection coefficient Reff to simplify the effect of external cavity, while the dynamic characteristic is simulated according to the modified rate equation. In this model, the simulation results showed that: The threshold current can be reduced from 9.04mA to 4.01mA when the external cavity grating reflectivity increased from 0.1 to 0.9. At the same time, the line width can be reduced to 95.27kHz 1.34kHz when it operate in 60mA. The laser linewidth decreases from 3.20kHz to 0.36kHz when the external cavity length increased from 2cm to 6cm. when the length of gain chip decrease from 600μm to 200μm, the laser linewidth decreases from 1.69kHz to 1.22kHz. Conclusions can be made that the external cavity feedback enhancement can reduce the threshold current and the laser linewidth. Increase the length of the external cavity can reduce the linewidth as well. Besides that, reducing the gain chip size can also contribute to the linewidth narrowing.As for the experiment, we have a three-stage device fabrication process. First of all, a InP gain chip is made because of its gain spectrum. Secondly, both PLC and FBG are made for the external cavity chip. At last, after screening the PLC and FBG, a external cavity semiconductor laser which has a extremely narrow linewidth based on FBG is packaged. There are three crucial problems to be solved. To fulfil the single factor a narrow reflectivity peak grating is made. To increase the coupling efficiency an optical lens is used for beam shaping. To make it work steadily current source and TEC which have high precision are used. According to the measurement results, we can see that the laser threshold current is about 12.37mA, the minimum line width is 100.281Hz, while the linewidth which shares the same structures made by William et al. is 1 kHz .
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49226
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	刘大鹏. 基于光纤光栅的外腔窄线宽半导体激光器[D]. 中国科学院大学,2015.

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