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

Area of Science:

• Optical Communications
• Photonics
• Signal Processing

Background:

• All-optical wavelength conversion (AOWC) is crucial for flexible wavelength routing in reconfigurable optical networks.
• Conventional polarization-diversity schemes demand precise branch matching, which is challenging in real-world hardware.
• Semiconductor optical amplifier-four-wave mixing (SOA-FWM) is a key technology for AOWC.

Purpose of the Study:

• To demonstrate a relaxed-tolerance AOWC scheme using SOA-FWM.
• To enable polarization-insensitive wavelength conversion for 10 Gbps OOK and QPSK signals.
• To overcome the stringent branch-matching requirements of traditional polarization-diversity systems.

Main Methods:

• Experimental demonstration of a relaxed-tolerance SOA-FWM AOWC scheme.
• Utilizing branch-resolved monitoring and calibrated equalization for OOK and QPSK signals.
• Employing real-valued amplitude and complex calibration coefficients for signal reconstruction and equalization.

Main Results:

• Reduced idler power fluctuation from 5.46 dB to 1.25 dB (OOK) and 7.67 dB to 1.49 dB (QPSK) due to polarization state of polarization (SOP) changes.
• Improved worst-case bit-error rate (BER) for OOK from 4.74×10⁻¹ to 3.80×10⁻⁹.
• Narrowed error vector magnitude (EVM) range for QPSK from 11.1%-41.5% to 12.0%-14.8%, with BER improving from 7.95×10⁻³ to 7.1×10⁻¹².

Conclusions:

• The developed SOA-FWM AOWC scheme effectively relaxes branch-matching requirements.
• The technique offers a practical solution for polarization-insensitive wavelength conversion in optical networks.
• This work provides a laboratory-scale proof of concept for more robust optical network components.