RF power fading mitigation for an IMDD multicarrier LR-PON

Area of Science:

• Optical Communications
• Signal Processing

Background:

• Chromatic dispersion in intensity-modulation direct-detection (IMDD) orthogonal frequency division multiplexing (OFDM) systems causes radio frequency (RF) power fading.
• This fading leads to non-uniform subcarrier performance and varied quality of service (QoS) for subscribers in frequency division multiple access (FDMA) systems.

Purpose of the Study:

• To enhance receiving performance in IMDD long-reach passive optical networks (LR-PONs).
• To equalize subcarrier receiving performance for a universal transmitter design.
• To mitigate the effects of RF power fading and chromatic dispersion.

Main Methods:

• Proposed and experimentally demonstrated a multicarrier code division multiple access (MC-CDMA) signal format.
• Incorporated a multicode interference (MCI) cancellation process.
• Tested the system in an IMDD LR-PON environment.

Main Results:

• Achieved equalization of receiving performance across all subcarriers.
• Enabled a universal transmitter design to support subscribers from back-to-back to 100 km.
• Demonstrated over 21.7 dB power budget under 20 dB RF power fading.
• Observed only approximately 2 dB sensitivity deviation.

Conclusions:

• The proposed MC-CDMA scheme with MCI cancellation effectively enhances performance in IMDD LR-PONs.
• The system provides robust and uniform service quality despite significant RF power fading.
• A universal transmitter design is feasible, simplifying central office infrastructure.