Performance Analysis of the New Flexible Double Weight (FDW) Code With Various Detection Techniques

In this paper, Spectral Amplitude Coding Optical Code Division Multiple Access (SACOCDMA) system performance is analyzed using a Flexible Double Weight (FDW) code with various detection techniques. In theoretical analysis, various types of noise such as Phase-Induced Intensity Noise (PIIN), shot noise, thermal noise, and Multiple-Access Interference (MAI) effects were considered. System performance was characterized by the Signal-to-Noise Ratio (SNR) and bit error rate (BER). The analysis results obtained using the Spectral direct detection (SDD) technique were compared with those obtained using the AND subtraction and Modified AND subtraction detection techniques. The comparison results revealed that the FDW code with the SDD technique can support more active users and can improve system performance compared with the AND subtraction and Modified AND subtraction detection techniques. The FDW code is compared to the previous OCDMA code, known as Enhanced Double Weight (EDW) code, in terms of the number of simultaneous users it can support. The FDW code can accommodate up to 52 simultaneous users which is a significant improvement over the EDW code’s capacity of 30 users. This represents a 73.33% improvement achieved through the use of SDD techniques. In simulation analysis, the results were exemplified by the simulation experiment of the BER performance in the system with the new FDW code. The BERs of the AND subtraction and Modified AND subtraction detection techniques were 1.63 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−05</sup> and 1.69 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−08</sup>, respectively, at a distance of 60 km, whereas the SDD technique’s BER was 2.29548 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−12</sup>, which could reach up to 60 km with bit rate of 10 Gbps.