基于双光子聚合技术的微纳长周期光纤光栅

Microfiber Long-period Grating Based on Two-photon Polymerization Technology

利用飞秒激光搭建的双光子聚合系统,成功制作出微纳长周期光纤光栅(MLPG)。该系统通过计算机控制三维位移平台完成结构的制作,可编程实现光栅的自动化制作,并全程监控光栅的制作过程。与传统制造方法相比,基于双光子聚合的制造方法,在光纤表面使光刻胶周期性的发生双光子聚合完成MLPG的制作。因此在形成光栅时不依赖光纤基底的变化,该长周期光栅(LPG)结构形成于光纤外表面,适用于不同种类光纤上的LPG制备。在直径为6.9μm的微纳光纤上制造了8个周期为95μm的光栅块,在1331 nm波长处观察到了13.5 dB的传输谱损耗峰。实验结果表明,MLPG的温度灵敏度与折射率灵敏度分别达到了1.39 nm/℃、2207.89 nm/RIU(RIU为单位折射率)。

In this paper,a two-photon polymerization system built using a femtosecond laser was used to fabricate a microfiber long-period fiber grating(MLPG).The system uses a computer to control the three-dimensional displacement platform to complete the structure production,is programmable to realize the automatic grating production,and monitors the grating production process throughout the process.To complete the fabrication of the MLPG,the two-photon polymerization of the photoresist periodically occurs on the surface of the fiber.Compared with the traditional manufacturing method,the grating manufacturing method based on two-photon polymerization did not depend on the changes of the fiber substrate.The long-period grating can be flexibly manufactured on the outer surfaces of different types of fibers.As an example,we fabricated eight grating blocks with a 95 μm period on a microfiber with 6.9 μm diameter.At 1331 nm,a transmission spectrum loss peak of 13.5 dB is observed.The experimental results show that the temperature and refractive index sensitivities of the MLPG are as high as1.39 nm/°C and 2207.89 nm/RIU(RIU is the unit refractive index),respectively.