基于磁流体填充微结构光纤的温度特性研究

Temperature sensitivity of microstructured optical fiber filled with ferrofluid

利用毛细现象将磁流体完全填充到六角形微结构光纤的空气孔中,分析了磁流体填充长度、浓度对其传导特性的影响.结合磁流体独特的热光效应,并对一定浓度、长度下填充的光纤进行了温度特性的研究.结果表明,随着温度的升高,透射谱1460nm处磁流体的吸收峰逐渐变浅.基于磁流体载液与表面活性剂对温度的不同敏感性,吸收峰左右两个边沿表现出不同的温度响应;在波长为1100—1700nm之间透射损耗与温度变化成线性关系,对于填充长度为10cm的微结构光纤,敏感度达到0.06dB/°C,且液体填充长度越长,灵敏度越高.该研究将微结构光纤与磁流体材料有机地结合起来,并利用填充材料自身的热光特性,实现了对透射谱的单边调谐,将其作为热光可调谐器件、滤波器等相关可调谐光子器件在光通信、光传感等领域将具有很大的应用潜力.因此,基于材料填充微结构光纤的研究可为探索新型全光纤光子器件的新技术和新结构提供有效的方法.

In this paper ferrofluid is infiltrated in the index-guiding microstructured optical fiber （MOF） by the well-known capillary force and air pressure. The influences of the length and concentration of filled fiber on its guidance property are analyzed. Based on the response of fluid refractive index to temperature, the temperature sensitivities of filled MOF with different lengths are investi- gated without applying any external magnetic field. The results show that the short-wavelength edge of the absorption spectrum near 1460 nm remains unchanged, while the long-wavelength profile is sensitive to the temperature and the transmission power of the filled MOF decreases with the increase of temperature. There is a linear relationship between temperature and transmission power of the filled MOF. For the device with a length of 10 cm, its temperature sensitivity reaches 0.06 dB/~C. Combining the excellent thermo-optic effect of ferrofluid with MOF, the single edge of the device could be tuned by the temperature. It is potential to be used as a thermo- optic modulator, filter, and other adjustable photonics device. Considering a large number of magnetically tunable ferrofluids available and the high degree of freedom in MOF design, ferrofluid-filled MOF shows still a great promise and underexplored possibilities for both basic and applied research, opening new perspectives in optical telecommunication, all-optical switching and fiber-optic sensing applications, such as magnetic field sensors. The present study can offer an effective method for the novel technique and structure of all-in-fiber photonic devices.