Fig. 1. Phase-preserving amplitude regeneration scheme based on MZIs with OPCs

Fig. 2. Design of silicon wire waveguide and optical coupler. (a) Cross-section and layout of rib silicon wire waveguide; (b) coupling efficiency versus coupling length

Fig. 3. Layout of silicon-based MZI regeneration chip

Fig. 4. PTF and phase disturbance curves of silicon-based MZI regeneration chip

Fig. 5. Performance comparison of three regeneration schemes. (a) PTFs; (b) phase disturbance curves

Fig. 6. Simulation system of regenerator for QPSK signal

Fig. 7. NRR curves of QPSK signal for three regeneration schemes

Fig. 8. Constellation diagrams of QPSK signal before and after regeneration at input signal-to-noise ratio of 16 dB. (a) Single MZI chip; (b) OPC-MZI scheme

Fig. 9. Curves of different parameters depending on input power. (a) A1/A2, ϕ1 and ϕ3; (b) Δθ=θ2-θ1

Fig. 10. Phase disturbance curves of regenerator before and after optimization when waveguide loss coefficient is increased to 0.5 dB/cm