Ultralow-Loss Power Splitters Based on Shape Optimization Method

We demonstrate two kinds of low-loss 1 × 4 optical power splitters based on multimode interference (MMI) couplers. By using the adjoint shape optimization method, the shapes of MMI couples are optimized to realize uniform power splitting and a splitting ratio of 1:2:4:8. Simulation results show that the insertion losses at the wavelength of 1550 nm are 0.04 dB and 0.17 dB for 1 × 4 uniform power splitter and 1:2:4:8 power splitter, respectively.