Cardinality Enhancement of SAC-OCDMA Systems Using New Diagonal Double Weight Code

Optical code division multiple access (OCDMA) provides  another dimension to multiple access systems,  in which each user is assigned a unique code. This allows  each subscriber  to simultaneously access the medium without any contention. However, simultaneous access of multiple users introduce multiple access interference  (MAI)  which primarily deteriorates  the performance of OCDMA systems.  This paper proposes a new code called diagonal double weight (DDW) code to elevate the performance and cardinality of spectral amplitude coding  (SAC) OCDMA  systems. Performance of our proposed code is evaluated using comprehensive analytical  analysis  followed by simulation analysis. Examination  of bit error rate shows that DDW code along with  single photodiode detection  technique  provides efficient performance, with added benefits of simplified design, large cardinality and ease of implementation

Enhanced probability density function using APD in SAC-OCDMA systems based SPD technique

This paper examines the avalanche photodiode (APD) gain impact on spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems based single photodiode detection (SPD) technique. Numerical results are used for inspecting the APD gain influence upon the probability density function (PDF) and signal-to-noise ratio (SNR) performance. The usage of APD over positive-intrinsic-negative (PIN) photodiode accommodates more users with improved PDF and higher SNR

Selective mode excitation in SCM-OCDMA

A six-channel 2.4GHz subcarrier multiplexing - optical code division multiple access (SCM-OCDMA) system in conjunction with the selective excitation of LP01 and LP02 modes is presented for a multimode fiber Local Area Network. Simulation results demonstrate that mode selectivity increases the bandwidth-distance product and improves the BER performance of the channel

Investigation of channel spacing for Hermite-Gaussian mode division multiplexing in multimode fiber

Mode division multiplexing (MDM) may be used to increase the capacity of multimode fiber interconnects for data centers.This paper demonstrates the importance of controlling the channel spacing of a MDM system capitalizing on Hermite-Gaussian (HG) modes in order to mitigate modal dispersion and minimize the average system bit-error rate.The effect of channel spacing of a 25-channel hybrid MDM-wavelength division multiplexing (WDM) system was examined through the x-index and y-index separations of Hermite polynomials of HG modes for different MMF lengths. Simulations prove that by controlling the index separations of the Hermite polynomials, acceptable BER was achieved for 25Gb/s data transmission for a distance of 800 meters for a 25-channel HG-based MDM-WDM system at a center wavelength of 1550.12nm.The optimal x-index and y-index Hermite polynomial separations for the HG modes are 2, 3 and 4

Improving spectral efficiency of SAC-OCDMA systems by SPD scheme

This letter presents a single photodiode detection (SPD) as an effective technique for eradicating both multiple-access interference (MAI) and phase-induced intensity noise (PIIN) in spectral amplitude coding optical code-division multiple-access (SAC-OCDMA) systems. Mathematical analysis and simulation experiments are used to investigate the spectral efficiency (SE) of SAC-OCDMA systems utilizing different detection techniques. Results show that the SPD technique significantly enhances the SE compared to AND as well as modified-AND subtraction detections