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

[2] B. Malo, K. A. Vineberg, K. O. Hill et al.. Efficient mode conversion in telecommunication fiber using externally written grating[J]. Electron. Lett., 1990, 26(16): 1270～1272

[3] A. M. Vengsarkar, P. J. Lemaire, J. B. Judkins et al.. Longperiod fiber gratings as bandrejection filters[J]. J. Lightwave Technol., 1996, 14(1): 58～64

[4] F. Bilodeau, K. O. Hill et al.. Efficient narrowband LP01～LP02 mode convertors fabricated in photosensitive fibre: Spectral response[J]. Electron. Lett., 1991, 27(8): 682～684

[7] I. Riant, L. Gasca, L. Gasca et al.. Gain equalization with optimized slanted Bragg grating on adapted fiber for multichannel longhaul submarine transmission[C]. OFC′99, 1999, THJ61:147～149

[8] Kristin Lewotsky. Longperiod gratings flatten fiberamplifier gain[J]. Laser Focus World, 1996, 32(4): 34～37

[9] Paul F. Wysocki, Justin B. Judkind, Rolando P. Espindola et al.. Broadband erbiumdoped fiber amplifier flattened beyond 40 nm using longperiod grating filter[J]. IEEE, Photon. Technol. Lett., 1997, 9(10): 1343～1345

[10] J. R. Qian, H. F. Chen. Gain flattening fiber filters using phaseshifted long period fibre gratings[J]. Electron. Lett., 1998, 34(11): 1132～1133

[11] H. Ke, K. S. Chiang, J. H. Peng. Analysis of phaseshifted longperiod fiber gratings[J]. IEEE Photon. Technol. Lett., 1998, 10(11): 1596～1598

[12] L. R. Chen. Design of flattop bandpass filters based on symmetric multiple phaseshifted longperiod fiber gratings[J]. Opt. Commun., 2002, 205: 271～276

[13] L. Tallone, L. Boschis, L. Gognolato et al.. Narrowband rejection filters through fabrication of inseries longperiod gratings[C]. Opt. Fiber Commun. Conf., 1997. 175

[14] Byeong Ha Lee, J. Nishii. Notch filters based on cascaded multiple longperiod fibre gratings[J]. Electron. Lett., 1998, 34(19): 1872～1873

[15] Y. Liu, J. A. R. Williams, L. Zhang et al.. Phase shifted and cascaded longperiod fiber gratings[J]. Opt. Commun., 1999, 164: 27～31

[16] O. Duhem, J. F. Henninot, M. Douay et al.. Study of in fiber MachZehnder interferometer based on two spaced 3dB long period gratings surrounded by a refractive index higher than that of silica[J]. Opt. Commun., 2000, 180: 255～262

[17] E. M. Dianov, S. A. Vasiliev, A. S. Kurkev et al.. Infiber MachZehnder interferometer based on a pair of longperiod gratings[C]. Proc. ECOC ′96, 1996, 1:65～68