Abstract: The new low-loss wide-angle Y-branch is designed and optimized in this paper, in detail. Device performance is examined numerically by finite-difference beam propagation method. The simulated results show the radiation loss of these devices is very small with relatively wide branching angle. At last a new 1×4 optical splitter composed of three new Y-branches is calculated. The simulation shows the new splitter has the characteristics of low-loss and simple-structure, and its length is decreased greatly.