Volterra predistorter for the dynamic nonlinearity of LED

Area of Science:

• Optical Communications
• Nonlinear Distortion Compensation
• Signal Processing

Background:

• Light-emitting diode (LED) communication systems are susceptible to second-order nonlinear distortion.
• Traditional equalization methods often require complex receiver-side processing.
• Improving the signal quality and power efficiency in LED communications is crucial.

Purpose of the Study:

• To propose and evaluate a Volterra predistorter for compensating second-order nonlinear distortion in LED communication systems.
• To demonstrate the reduced numerical processing complexity of the proposed predistorter.
• To compare the performance of the predistorter with a classical Volterra equalizer.

Main Methods:

• Application of a Volterra predistorter specifically designed for LED systems.
• Experimental investigation using pulse amplitude modulation (PAM-4).
• Performance evaluation based on electrical signal to noise and interference power ratio (SINR) and optical power penalty.

Main Results:

• The proposed predistorter exhibits linear numerical processing complexity, unlike quadratic complexity in classical Volterra equalizers.
• The predistorter achieved performance comparable to a receiver-side Volterra equalizer.
• A maximum gain of approximately 3.5 dB in SINR was measured at 300 Mbaud.
• The unpredistorted signal showed a power penalty of up to 2.5 dBm compared to the predistorted signal at 300 Mbaud.

Conclusions:

• The Volterra predistorter effectively compensates for second-order nonlinear distortion in LED communication systems.
• The proposed approach offers a computationally efficient solution with performance on par with existing methods.
• This technique significantly reduces power penalties, enhancing the overall efficiency of LED communication.