Anuar Mat Safar

Mitigation of multiple access interference using two-dimensional modified double weight codes for optical code division multiple access systems

We proposed newly two-dimensional (2- D ) spectral amplitude coding optical code division multiple access (OCDMA) scheme using modified double weight (MDW) code capable of suppressing phase-induced intensity noise (PIIN). The architecture of the spectral/spatial MDW OCDMA system with the property of multi-access interference cancellation is presented. The proposed code exhibits good cross-correlation property. At the optimized data transmission rate of 0.745 Gbps, 2-D MDW, M = 63, N = 3, reaches maximum cardinality of 200% increases compared to 2- D perfect difference code, M = 57, N = 3. The performance is severely deteriorated if the data rate further increases above 0.745 Gbps. The proposed code meets the optical transmission requirements at 10−9 bit error rate error floor, with lowest effective transmitted power ( P sr), −17.5  dBm, in comparison to the others through minimizing interference noise that result in PIIN suppression. The proposed system reaches optimum requirements performance in terms of cardinality, data transmission rate, and low effective transmitted power.

Performance Analysis of an OCDMA System Based on SPD Detection Utilizing Different Type of Optical Filters for Access Networks

This paper aims to study the performance of spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems based on single photo-diode (SPD) detection under various types of optical filters decoder schemes (Optical Gaussian filter, Thin film and Fiber Bragg Grating (FBG)). In our work, we utilized Modified Double weight (MDW) code as one of the SAC codes; the proposed system is performed by using single photodiode for each user. The results characterizing the bit-error-rate (BER) of 10−12 with respect to the data rate show that the SDP offers a significant improved performance for long haul applications (wide area network (WAN)) over other types of SAC-OCDMA detection techniques. Furthermore, the FBG filters have higher dispersion than Gaussian and thin film filters. The comparison states that the optical Gaussian filters have better filter amplitude response leading to lower dispersion bandwidth reduction, while FBG filters have higher dispersion which could reduce the goal of 622 Mbps channels in SPD detection scheme.

20 Gb/s optical OFDM transmission for long haul transmission

Optical OFDM system is considered to be the essential backbone of the next generation of ultra-high-speed networks. A dispersion effect is considered one of the common limitations in optical OFDMA system especially at very high date rate. When the pulse width reaches less than a few pico-seconds, not only the second-order but even higher-order dispersion must be taken into account. In this paper OOFDM system designed with traditional dispersion compensating devices such as Dispersion compensating fiber (DCF) used in multi spans with single mode fiber to reach to 288 km distance at 20 Gb/s. moreover, single side band (SSB) used to reduce the dispersion as well. Therefore, the overall system performance based on SNR, spectral analyzer and constellation diagram for the single side band (SSB) OOFDM system gives a good result with 16 QAM modulation.

QoS measurements based single photodiode detection for SAC-OCDMA systems under long haul applications

The intent of this paper is to study the performance of spectral-amplitude coding optical code-division multiple-access (OCDMA) systems using Single Photodiode Detection (SPD) under various optical parameters. In our work, we utilized Modified Double weight (MDW) code as one of the OCDMA applications which called “triple-play” services (audio, video, and data) with different quality-of-service (QoS) requirements; this service is performed by using single photodiode for each user. The results characterizing the bit-error-rate (BER) with respect to the data rate show that the SDP offers a significant improved performance for ultra-high speed application at (800 Mbps) over other types of detections. Furthermore, this system can transmit up to 110 km at BER of 10-9.