通过分析单模光纤SMF中的LPG对的传输特性及几个因素对干涉透射谱的影响,并结合前期工作,主要研究光子晶体光纤(PCF)中的LPG对在1665 nm附近U波段传输特性。结合光栅耦合强度与波长的关系以及拍长与波长的关系,对PCF中LPG对的参数进行选择设计,得到双谐振波长的干涉谱,级联LPG对构成的MZI干涉光谱在两个谐振波长处由于耦合强度不同而不同。

The propagation properties of the long-period fiber grating (LPG) pair in standard single-mode fiber (SMF) are discussed including some factors affecting the interference transmission spectra,and the characteristics of the LPG pair in the photonic crystal fiber (PCF) at the U-band near 1665 nm are investigated in detail. A dual resonance interference spectrum is obtained after the structural parameters of the LPG pair in PCF are designed based on the relation between coupling strength and the beat length as well as the relation between beat length and wavelength. The spectra at both resonance wavelength are different due to the different coupling strength.