摘要
实验制备了基于细芯光纤（TCF）的马赫-曾德尔干涉仪（MZI）并进行了多参数测量传感研究。传感器采用两段单模光纤（SMF）进行腰椎放大连接细芯光纤,形成MZI结构。利用TCF与SMF的纤芯直径不匹配,在第1个接点激发出包层模式,包层模在第2个接点耦合进纤芯与纤芯模产生干涉,利用干涉条纹的波长漂移实现对外界环境参量的测量。实验所用的TCF纤芯的掺Ge浓度较高（约为38mol.%）,相对折射率和热光系数较普通SMF大,所以在保证适当的自由光谱范围（FSR）的前提下,TCF的长可以减小到2 mm,传感头尺寸较小,且传感结构对于温度的变化十分敏感。实验结果表明,在30~250℃的温度范围内,其温度灵敏度为70.2pm/℃,并具有较好的线性响应度。测试了传感器对折射率、应变和弯曲的响应,获得的灵敏度分别为-8.12nm/RIU、1.8pm/με和2.07nm/m-1。
A Mach-Zehnder interferometer （MZI） based on thin-core fiber is experimentally demonstrated and used for measurement of temperature, strain, surrounding refractive index and bending. The thin-core fiber （TCF） was sandwiched between two single mode fibers （SMFs） through two waist-enlarged bita- pers to form an MZI. Due to the core diameter mismatching between the two fibers,cladding modes are excited at the first splicing point and then coupled into the fiber core at the second splicing point to gen- erate interference. Wavelength shift of the interference fringes was used to measure the change of ambi- ent parameters. Since the core of the TCF contains Germania with mode percent of 38 ~,it has a rela- tively higher differential refractive index and higher thermal-optic coefficient compared with normal fi- bers. As a result,by ensuring an appropriate free spectral range （FSR） ,relatively short length of sensing fiber （2 ram） and relatively higher temperature sensitivity can be expected. Experimental results show that the temperature sensitivity is up to 70. 2 pm/℃ in a range from 30℃ to 250℃. The sensor responses to refractive index, strain and bending were also measured, and the achieved sensitivities are -8. 12 nm/RIU,1.8 pm/με and 2. 07 nm/m^-1 ,respectively.
出处
《光电子．激光》
EI
CAS
CSCD
北大核心
2016年第6期587-592,共6页
Journal of Optoelectronics·Laser
基金
国家自然科学基金(61475147)
浙江省自然科学基金(Z13F050003)
中国科学院天文光学技术重点实验室开放课题基金资助项目
关键词
光纤传感
细芯光纤(TCF)
多参数测量
腰椎放大熔接
optical fiber sensing
thin-core fibers （TCF）
multi-parameter measurement
waist-enlarged fusion splicing
