采用非对称Y分支波导和多模干涉型耦合器级联的方案设计出了一种光纤到户用单纤三向复用器芯片.模拟光谱响应结果表明,三个波长输出光斑清晰，实现了1 490 nm和1 550 nm下行波长的下传和1 310 nm波长的上传.有限差分束传播法模拟结果表明:该器件插入损耗小于1.49 dB,三个响应波长的带宽满足ITU.984 规定的带宽要求;1 310 nm上传信号隔离度达到47 dB以上，1 490 nm与1 550 nm间信号隔离度达到29 dB以上.

A triplexer was fabricated based on asymmetric Y branch waveguides Cascade Multimode interference(MMI) for fiber to the home(FTTH). The simulation results of spectral response show that output optical fields are clearly. And the demultiplexing function for download 1 490 nm and 1 550 nm and multiplexing function for upload 1 310 nm were achieved. The simulation results of finited different beam propagation method (FD-BPM) show that insertion loss is less than 1.49 dB; the bandwidths of three response wavelengths meet the demand of ITU. 984 completely; the isolation for 1 310 nm is more than 47 dB; the isolation for between 1 490 nm and 1 550 nm is more than 29 dB.