Evaluating LDPC Codes for OFDM/QAM Optical Fiber Systems

Optical fiber communications are a critical infrastructure for modern data transmission, providing high throughput and exceptional reliability over long distances. However, the integrity of the transmitted data remains vulnerable to distortion, which increase the bit-error-rate (BER). This effectively arises due to the increased dispersion resulted by the increase in the bit rate. Several correction codes have been developed to overcome this limitation, such as Manchester, Reed-Solomon, and Reed-Muller, however most of them suffer from significant drawbacks including high complexity, power consumption, and suboptimal error correction capabilities. The low density parity check (LDPC) code has been introduced as an effective coding technique to overcome the aforementioned limitation due to its attractive features, such as iterative decoding and parallel processing. This paper aims to verify the effectiveness of the LDPC code by applying it side by side with other codes designed for the same purpose on an OFDM/QAM-based optical communications system and comparing the performance. The performance is examined based on BER and constraints using Optisystem software. The results confirmed the superiority of the LDPC code as it shows lower BER, which contributes to increasing the transmission distance.