Journal of Applied Sciences ›› 2013, Vol. 31 ›› Issue (3): 239-244.doi: 10.3969/j.issn.0255-8297.2013.03.004

• Communication Engineering • Previous Articles     Next Articles

Three-Core LPFG Coupled Mode and Effective Refractive Index Calculation Method

WANG Xue1, LIU Ke-qiang2   

  1. 1. Periodicals Agency, Shanghai University, Shanghai 200444, China
    2. Shanghai Radio Equipment Research Institute, Shanghai 200090, China
  • Received:2012-11-09 Revised:2013-01-12 Online:2013-05-28 Published:2013-01-12

Abstract: Based on the coupled-mode theory, we study the coupling of three-core long period fiber gratings with two different structures and derive the mode coupling equations. The calculation method of cladding mode’s effective refractive index is also investigated. The rule of cladding mode’s effective refractive index
change with the wavelength is discussed by numerical simulation. The results show that, the indices of both odd and even modes reduce as the wavelength increases. Different arrangements of three cores affect the extent of the index decrease. The results of this study provide theoretical guidance to the application of three-core fiber LPFG.

Key words: long period fiber grating (LPFG), coupled mode, three-core fiber

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