[1] [1] N D Rees, S W James, R P Tatam, et al.. Optical fiber long-period gratings with Langmuir-Blodgett thin-film overlays［J］. Opt Lett, 2002, 27(9): 686-688.

[2] [2] I D Villar, M Achaerandio, I R Matias, et al.. Deposition of overlays by electrostatic self-assemble in long-period fiber gratings［J］. Opt Lett, 2005, 30(7): 720-722.

[3] [3] H Y Chen, Z T Gu. Design of a gas sensor based on a cladding-reduced long period fiber grating coated with a sensitive film ［J］. Optik, 2013, 124(3): 219-224.

[4] [4] Deng Hongyou. The Sensor Based on Thin-Cladding Long Period Fiber Grating [D]. Chengdu: University of Electronic Science and Technology of China, 2008. 54-62.

[5] [5] Deng Chuanlu, Gu Zhengtian, Zhang Jiangtao. Resonant characteristics and optimization of long period fiber grating coated with weak absorption double-layer films ［J］. Acta Photonica Sinica, 2009, 38(11): 2873-2879.

[6] [6] A Cusano, A Iadicicco, P Pilla, et al.. Coated long-period fiber gratings as high-sensitivity optochemical sensors ［J］. J Lightwave Technol, 2006, 24(4): 1776-1786.

[7] [7] Z T Gu, Y P Xu, K Gao. Optical fiber long-period grating with solgel coating for gas sensor［J］. Opt Lett, 2006, 31(16): 2405-2407.

[8] [8] Jiang Xiuli, Gu Zhengtian. Impact of thin film extinction coefficient on coated long-period fiber grating transmission spectrum ［J］. Acta Optica Sinica, 2010, 30(8): 2189-2195.

[9] [9] I Del Villar, I R Matias, F J Arregui, et al.. Optimization of sensitivity in long period fiber gratings with overlay deposition ［J］. Opt Express, 2005, 13(1): 56-69.

[10] [10] A Cusano, A Iadicicco, P Pilla, et al.. Mode transition in high refractive index coated long period gratings［J］. Opt Express, 2006, 14(1): 19-34.

[11] [11] Yu Xiujuan, Zhang Min, Wang Liwei, et al.. Characteristics of long-period optical fiber grating with high refractive index nm-thick film overlay ［J］. Acta Optica Sinica, 2009, 29(10):2665-2672.

[12] [12] P Pilla, C Trono, F Baldini, et al.. Giant sensitivity of long period gratings in transition mode near the dispersion turning point: an integrated design approach［J］. Opt Lett, 2012, 37(19): 4152-4154.

[13] [13] Xu Yanping, Gu Zhengtian, Chen Jiabi. Effect of surface film optical parameters on the characteristic of long-period fiber grating ［J］. Chinese J Lasers, 2005, 32(11): 1519-1524.

[14] [14] I Del Villar, I R Matias, F J Arregui. Influence on cladding mode distribution of overlay deposition on long-period fiber gratings ［J］. J Opt Soc Am A, 2006, 23(3): 651-658.

[15] [15] T Erdogan. Cladding-mode resonance in short-and-long-period fiber grating filters ［J］. J Opt Soc Am A, 1997, 14(8): 1760-1773.

[16] [16] Z T Gu, Y P Xu. Design optimization of a long-period fiber grating with sol-gel coating for a gas sensor ［J］. Meas Sci & Technol, 2007, 18(11): 3530-3536.