Relaxed-tolerance polarization-insensitive all-optical wavelength conversion using SOA-FWM with weighting-assisted...

Polarization-insensitive all-optical wavelength conversion (AOWC) is essential for flexible wavelength routing in reconfigurable optical networks, including potential satellite optical networks. However, conventional polarization-diversity schemes require stringent matching between parallel conversion branches, which is difficult to maintain under practical hardware constraints. Here we experimentally demonstrate a relaxed-tolerance four-wave mixing in semiconductor optical amplifiers (SOA-FWM) AOWC scheme for 10 Gbps OOK and QPSK signals using branch-resolved monitoring and calibrated equalization. For OOK, a real-valued amplitude coefficient is estimated from the aligned branch waveforms and mapped to the optical amplitude-control units (ACUs). For QPSK, a complex calibration coefficient is determined from the synchronously acquired branch records; its magnitude sets the ACU's adjustment, whereas the complete coefficient is used for offline complex-field reconstruction. At an optimized operating point of -2.58 dBm signal power, 11.61 dBm pump power, and 350 mA SOA current, the state-of-polarization (SOP) induced idler power fluctuation is reduced from 5.46 dB to 1.25 dB for OOK and from 7.67 dB to 1.49 dB for QPSK. Across four representative SOP conditions, the worst-case estimated bit-error rate (BER) of the converted OOK idler is reduced from 4.74 × 10^-1 to 3.80 × 10^-9. For QPSK the error vector magnitude (EVM) range is narrowed from 11.1%-41.5% to 12.0%-14.8%, while the worst-case estimated BER decreases from 7.95 × 10^-3 to 7.1 × 10^-12. The penalties observed at initially favorable SOPs reflect the trade-off between output-power equalization and best-case signal quality. These results provide a laboratory-scale proof of concept for relaxing branch-matching requirements in polarization-diversity SOA-FWM converters.