Performance evaluation of an IMDD optical OFDM-CDMA system

Area of Science:

• Optical communication networks
• Signal processing in telecommunications
• Multiplexing techniques

Background:

• Passive optical networks (PONs) are crucial for broadband access.
• Increasing demand for higher user capacity in PONs presents a challenge.
• Current multiplexing techniques face limitations in cost-effectiveness and capacity.

Purpose of the Study:

• To propose a novel modulation technique for PONs.
• To enhance user signal capacity in a cost-effective manner.
• To analyze the performance of the proposed technique under multiple-access interference and noise.

Main Methods:

• Harnessing two-dimensional prime hop system optical code division multiplexing access (OCDMA).
• Integrating optical orthogonal frequency-division multiplexing (OFDM) for intensity modulation with direct-detection (IMDD).
• Developing a theoretical analysis using an analytical formula accounting for multiple-access interference and photodetector noise.

Main Results:

• The proposed OFDM-OCDMA technique effectively enhances user signal capacity.
• Theoretical analysis provides insights into performance limitations due to interference and noise.
• Performance of multi-user OFDM-OCDMA is comparable to single-user conventional OOFDM at low transmitted powers.

Conclusions:

• The combined OFDM-OCDMA modulation technique offers a cost-effective solution for increasing capacity in passive optical networks.
• The theoretical framework accurately models system performance.
• The technique shows promise for future broadband access networks, especially under specific power conditions.