[1] Qian J R,Chen H F. Gain flattening fibre filters using phase-shifted long period fibre gratings.Electron Lett,1998,34(11):1132～1122

[2] Vengsarkar A M,Lemaire P J,Judkins J B,et al. Long-period fiber gratings as band-rejection filters.J Lightwave Technol,1996,14(1):58～65

[3] Bhatia V, Vengsarkar A M. Optical fiber long-period grating sensors. Opt Lett,1996,21(9):692～694

[4] Gu X J. Wavelength-division multiplexing isolation fiber filter and light source using cascaded long-period fiber gratings.Opt Lett,1998,23(7):509～510

[5] Wysocki P F,Judkins J B,Espindola R P,et al. Broad-band Erbium-doped fiber amplifier flattened beyond 40 nm using long-period grating filter. IEEE Photon Technol Lett,1997,9(10):1343～1345

[6] Vengsarkar A M,Pedrazzani J R,Judkins J B,et al. Long-period fiber-grating-based gain equalizers.Opt Lett,1996,21(5):336～338

[7] Michiko Harumoto,Masakazu Shigehara,Hiroshi Suganuma. Gain flattening filter using long-period fiber gratings.J Lightwave Technol,2002,20(6):1027～1032

[8] Hand D P,Russell P St J. Photoinduced refractive-index changes in germanosilicate fibers.Opt Lett,1990,15(2):102～104