针对激光器频率调谐系数测试应用的需求,提出了基于空心光子晶体光纤的激光器频率调谐系数测试装置的方案。首先,对测试装置的总体方案、光子晶体光纤谐振腔的基本结构进行设计,重点完成了激光器频率调谐系数测试方法的数值计算和机理分析;之后,完成了光子晶体光纤谐振腔的设计和加工,并搭建了激光器频率调谐系数测试装置;最后,对目前常用的窄线宽光纤激光器和半导体激光器进行频率调谐系数测试。光纤激光器的电压-频率调谐系数为17.6 MHz/V,与激光器出厂指标基本吻合,而且光纤激光器的频率调谐系数在调谐范围内具有良好的一致性。半导体激光器在调谐范围内的调谐系数不均匀,容易受环境的影响,测得电流-频率调谐系数的平均值为30.9 MHz/mA。研究结果表明,测试装置的精度远高于商用波长计,并且具有良好的长期稳定性,充分体现出了空心光子晶体光纤谐振腔作为频率基准进行频率检测所具有的测频精度高、温度漂移小的技术优势。

In this study, a scheme for measurement equipment based on hollow photonic crystal fiber was proposed to meet the measurement requirement of laser frequency tuning ratio. First, the scheme of the measurement equipment and basic structure of the photonic crystal fiber resonator (PCFR) were designed and the numerical calculation and mechanism analysis of the laser frequency tuning ratio were completed. Second, PCFR was designed and manufactured, and the laser frequency tuning ratio testing setup was constructed. Finally, the frequency tuning ratio of narrow line-width fiber laser and semiconductor laser were tested. The voltage-frequency tuning ratio of the fiber laser is 17.6 MHz/V, which is in accordance with the factory indicators; moreover, the fiber laser''s tuning ratio is consistent at the tuning range. The tuning ratio of semiconductor laser in tuning range is non-consistent, which is susceptible to environmental influences. The average current-frequency tuning ratio of the semiconductor laser is 30.9 MHz/mA. This study demonstrates that the accuracy of the proposed testing setup is much higher than that of the commercial wavelength meter, and it also displays good long-term stability. Furthermore, PCFR has technical advantages, such as high frequency measurement accuracy and small temperature drift, as a frequency reference for frequency tuning ratio detection.