Ideas about applications of LPFG to band-pass filters, optical add/drop multiplexing, optical fiber sources, coupling of阐明了长周期光纤光栅用于带通滤波、光上下路复用、光纤光源、光纤耦合、偏振器件、新型传感等新技术领域的思路，给出了具体实现方法。
The structure of band-pass RAKE receiver and the model of demodulation are depicted.我们给出带通犁耙式接收机模型及解调结构。