Fig. 7.

a Schematic diagram of a Bell state generator, which consists of tunable beamsplitters and Bell-state measurement (BSM), which can also serve as type-II fusion of two entanglement systems. The scheme is compatible with the T-MUX bleeding technique. b Heralded generator of in polarization-encoded Bell states proposed in [91], which is compatible with T-MUX bleeding and boosting operations. c Schematic diagram of type-I fusion gate and d corresponding experimental setup of c in polarization-encoded qubits. BS, beam splitter; DFT, discrete Fourier transform; HWP, half-waveplate; PBS, polarizing beamsplitter