[4] Rao Y J,Wang Y P,Ran Z L, et al.Novel fiber-optic sensors based on long-period fiber gratings written by high-frequency CO2 laser pulses.J of Lightwave Technology,2003,21(5):1320~1325
[5] Liu H B,Liu H Y,Whitbread T,et al.A simple stain sensor using polymer fiber Bragg grating and long-period fiber grating.Advanced Sensor Systems and Application Ⅱ. Proc of SPIE,2004,5634:123~127
[7] Shu X W,Zhang L,Bennion I.Fabrication and characteristics of ultra-long-period fibre gratings.Optics Communications,2002,203(3-6):277~281
[8] Rao Y J,Wang Y P,Ran Z L,et al.Characteristics of novel long-period fiber gratings written by focused high-frequency CO2 laser pulses.Asia-Pacific Optical and Wireless Communications,2001, Proc of SPIE,2001,4581:327~333
[9] Trevor W M,Saeed P,Charles W H,et al.Generalized expression for the growth of long period gratings.IEEE Photonics Technology Letters,1998,10(10):1449~1451