Non-rectangular perfect reconstruction pulse shaping based ICI reduction in CO-OFDM.

Area of Science:

• Electrical Engineering
• Optical Communications
• Signal Processing

Background:

• Coherent optical-orthogonal frequency division multiplexing (CO-OFDM) systems are susceptible to residual carrier frequency offset (RCFO).
• RCFO introduces performance degradation, limiting transmission distance and system reliability.
• Existing methods to mitigate RCFO often require additional overhead or complex signal processing.

Purpose of the Study:

• To propose and evaluate a novel pulse shaping technique for enhancing RCFO tolerance in CO-OFDM systems.
• To suppress RCFO-induced penalties at the receiver without additional overhead or complex signal processing.
• To quantify the performance improvements in terms of Q-factor and transmission span gain.

Main Methods:

• Utilizing short perfect reconstruction pulse shaping techniques.
• Implementing time-frequency localization maximization and out-of-band energy minimization pulse shapes.
• Analyzing the impact of RCFO on system performance at the receiver.

Main Results:

• Achieved a Q-factor improvement of 1.6 dB with time-frequency localization maximization pulse shapes.
• Achieved a Q-factor improvement of 1.8 dB with out-of-band energy minimization pulse shapes.
• Demonstrated a transmission span gain of approximately 62% with out-of-band energy minimization pulse shapes under RCFO.

Conclusions:

• The proposed short perfect reconstruction pulse shaping effectively increases RCFO tolerance in CO-OFDM systems.
• The method offers significant performance gains without compromising spectral efficiency or increasing receiver complexity.
• This technique provides a practical solution for extending the reach of high-speed optical communication systems.