[1] [1] Jinguji K. Planar lightwave circuits. Nippon Telephone and Telecommunication Review, 1995, 7(1):80～86

[2] [2] Kobayashi I, Tsuji H. Research and development of fiber optic subscriber network systems. Nippon Telephone Telecommunication Research & Development, 1993, 42(7):849～856

[3] [3] Miki T. Toward the service-rich era. IEEE Commun. Mag., 1994, 32(2):34～39

[6] [6] Weissman Z, Marom E, Hardy A. Very low-loss Yjunction power divider. Opt. Lett., 1989, 14(5):293～295

[7] [7] Hung W Y, Chan H P, Chung P S. A novel design of wide-angle single-mode symmetric Y-junctions. Electron. Lett., 1988, 24(15):1185～1186

[8] [8] Chung P S, Chan H P, Pun E Y B. Novel design of integrated optical beam splitters using symmetric Y-branch structures. IEEE Proc., 1990, 137(5):340～344

[9] [9] Chan H P, Chung P S, Pun E Y B. Design of 3-dB integrated optical couplers in asymmetric branching waveguides. Jpn. J. Appl. Phys., 1992, 31(5B):1641～1642

[12] [12] Tsuji M, Tanaka O, Shigesawa H. Low-loss design method of planar dielectric waveguide Y-branch: Effect of serpentine-shaped taper. IEEE Trans. Microwave Theory Tech., 1991, MTT-39(1):6～13

[13] [13] Chung Y, Dagli N. An assessment of finite different beam propagation method. IEEE J. Quant. Electron.,1990, QE-26(8):1335～1339