Dual-polarization MZM-based photonic nonlinear analog self-interference cancellation for in-band full-duplex radios

Area of Science:

• Photonics
• Optical Communications
• Signal Processing

Background:

• In-band full duplex (IBFD) systems require effective self-interference cancellation (SIC) to mitigate performance limitations caused by analog circuit nonlinearities.
• Existing analog SIC techniques struggle to compensate for complex nonlinear distortions inherent in IBFD systems.

Purpose of the Study:

• To propose and validate a novel dual-polarization Mach-Zehnder modulator-based photonic nonlinear analog SIC technique.
• To overcome performance bottlenecks in IBFD systems stemming from analog SIC circuit nonlinearity.

Main Methods:

• Utilizing a dual-polarization Mach-Zehnder modulator to generate an arbitrary 4th order nonlinear transfer function.
• Imitating the nonlinear transfer function of the analog SIC circuit before the cancellation process.
• Conducting performance analysis via simulations and a proof-of-concept experimental demonstration.

Main Results:

• Achieved 29 dB of self-interference cancellation over a 500 MHz bandwidth at 1.25 GHz.
• Demonstrated effective compensation for various degrees of nonlinearity-induced distortion.
• Simulation results based on experimental data showed over 3 dB of signal-of-interest (SOI) power gain, evaluated by error vector magnitudes (EVMs).

Conclusions:

• The proposed photonic nonlinear analog SIC technique effectively overcomes nonlinearity limitations in IBFD systems.
• The technique offers significant improvements in cancellation performance and SOI power gain.
• This approach presents a viable solution for enhancing the performance of future wireless communication systems.