In future high capacity multicore optical fiber (MCF) networks, signal-processing devices should be able to manipulate data without sacrificing network capacity or MCFs advantages. Thus, it is crucial to have high performance novel devices that can be connected directly to MCFs without conversion to conventional single-core fibers. In this work, a novel Y-splitter for multicore optical fibers is proposed and numerically demonstrated for the first time. The splitter can directly split the power of input MCF cores by 50/50 splitting-ratio into two output MCFs cores. The splitter principle of operation mainly depends on novel double-hump graded-index (DHGI) profile that can space-division split (SDS) optical power by half. Both finite-difference-time-domain and eigenmode-expansion simulations are performed to design, verify, and characterize performance of Y-splitter. It shows wideband operation over the S, C, L, U-bands with polarization insensitivity. It also demonstrates high performance with reasonable insertion-loss, in addition to very low excess-loss and return-loss. Moreover, the splitter shows good performance tolerance to both MCF and design parameters variations.