[1] Shinohara H. Broadband access in Japan: rapidly growing FTTH market. IEEE Communications Magazine, 2005, 43(9): 72-78

[2] Dong L, Hua P, Birks T A, Reekie L, Russell P S J. Novel add/drop filters for wavelength-division-multiplexing optical fiber systems using a Bragg grating assisted mismatched coupler. IEEE Photonics Technology Letters, 1996, 8(12): 1656-1658

[3] Ahn SW, Shin S Y. Grating-assisted codirectional coupler filter using electrooptic and passive polymer waveguides. IEEE Journal of Selected Topics in Quantum Electronics, 2001, 7(5): 819-825

[4] Erdogan T. Cladding-mode resonances in short- and long-period fiber grating filters. Journal of the Optical Society of America A, 1997, 14(8): 1760-1773

[5] Chen G X, Liu C N, Li T J, Zhang J S, Jian S S. Study on long-period fiber gratings. Acta Optica Sinica, 2000, 20(5): 624-628 (in Chinese)

[6] Kulishov M, Daxhelet X, Grubsky V, Srhwartz J, Plant D V. Distinctive behavior of long-period gratings in amplifying waveguides. In: Proceedings of Optical Fiber Communication Conference 2005. 2005, OTuB7

[7] Greenberg M, Orenstein M. Unidirectional complex grating assisted couplers. Optics Express, 2004, 12(17): 4013-4018

[8] Snyder A W, Ankiewicz A. Optical fiber couplers-optimum solution for unequal cores. Journal of Lightwave Technology, 1988, 6(3): 463-474