In this paper, a compact triplexer is proposed by cascading three tilted multimode interference couplers for FTTH applications. AH components based on silicon rib waveguides. Firstly, a MMI coupler is designed to separate the 1310 nm wavelength band by using pseudo self-imaging technique. A tiled MMI coupler is then cascaded to separate the 1490 nm and 1550 nm wavelength bands. Numerical simulations are utilized three-dimensional beam propagation method (3D-BPM) incorporated with effective index method (EIM) for designing and optimizing the whole device. Simulation results show that an optical performance of the device satisfies with ITU G.983 recommendation.