报道了一种基于偏芯结构的双芯光纤制作的长周期光纤光栅，研究了在这种双芯光纤中写入相同结构的长周期光纤光栅的模式耦合特性，这种双芯结构能够将两个平行的长周期光纤光栅集成在一根光纤中。通过模拟计算发现在光纤圆周横截面不同方位进行曝光，可获得不同的光栅透射谱，通过利用CO2激光脉冲曝光方法实现其制备，实验得出了采用单侧曝光方法在偏芯结构的双芯光纤上制备长周期光纤光栅的最佳写入方式。通过理论分析和实验的对比，结果表明，双芯长周期光纤光栅透射谱依赖于在双芯光纤圆周上的曝光方向。

A twin-core fiber-based long period fiber grating has been proposed. It makes two long-period gratings in parallel and integrates the two components in one fiber. The mode coupling between two same pattern long-period fiber gratings in this twin-core fiber is also investigated. Simulation results show that different transmission spectrum with three different exposure directions on circular cross section of the fiber can be obtained. The twin-core long-period fiber grating is fabricated by using CO2 laser pulse exposure approach. The best way to achieve this twin-core long period fiber grating is also given by experiment.It is shown that the transmission spectrum characteristics of the two long-period gratings written in the twin-core fiber depend on the CO2 laser pulses exposure direction on the fiber circumference.