[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 Del Villar, I R Matias, F J Arregui. Optimization of sensitivity in long period fiber gratings with overlay deposition[J]. Opt Express, 2004, 13(1): 56-69.

[3] [3] 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.

[4] [4] 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.

[5] [5] 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.

[6] [6] Y Qian, Y S Yu, Q S Li, et al.. High sensitive long period fiber grating sensor for detection of nitrite[J]. Chem Res Chinese Universities, 2009, 25(5): 624-627.

[7] [7] J C Yang, C Y Tao, X M Li, et al.. Long-period fiber grating sensor with a styrene-acrylonitrile nano-film incorporating cryptophane A for methane detection[J]. Opt Express, 2011, 19(15): 14696-14706.

[8] [8] S M Tripathi, W J Bock, P Mikulic, et al.. Long period grating based biosensor for the detection of Escherichia coli bacteria[J]. Biosens Bioelectron, 2012, 35(1): 308-312.

[9] [9] Zhang Zijia, Xu Autao. Sensitivity of the thin-cladding long period fiber gratings to refractive index[J]. Chinese J Sensors & Actuators, 2009, 22(8): 1105-1108.

[10] [10] Zhang Le, Wu Bo, Ye Wen, et al.. Highly sensitive fiber-optic vibration sensor based on frequency-locking of a FBG Fabry-Perot cavity[J]. Acta Optica Sinica, 2011, 31(4): 0406006.

[11] [11] Gu Zhengtian, Zhang Jiangtao. Metal-coated long-period fiber grating liquid sensor based on dual-peak resonance[J]. Acta Optica Sinica, 2011, 31(3): 0305003.

[12] [12] Zhao Minfu, Zhang Guiju, Ma Difeng. Single-ended LPFG refractive index sensor based on metal-coated surface plasma resonance[J]. Opto-Electronic Engineering, 2009, 36(7): 144-150.

[13] [13] Gu Zhengtian, Lan Jinlong. Mode transition in absorption film coated long-period fiber grating and response characteristics of refractive index[J]. Acta Optica Sinica, 2013, 33(7): 0706003.

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