No abstract

No abstract

Bandwidth assignment is a key issue in optical access networks, so an efficient mechanism is required for dynamic distribution of limited resources in the uplink channel among competing subscriber optical network units (ONUs). This paper presents a novel optimized dynamic bandwidth allocation (ODBA) algorithm for hybrid WDM/TDM passive optical networks. ODBA algorithm operates using information frame length of the subscriber’s ONUs and their information arrival rate; both of these factors finalize the assigned transmission capacity to the users. The system performance under differing offered traffic loads is evaluated in terms of network throughput, average delay and channel utilization. Further, the proposed ODBA scheme is validated by performing a comparative analysis with well-known algorithms.

Abstract-Free-space optical (FSO) communication is a cost effective and high data rate access technique, which has been proving itself a best alternative to radio frequency technology. FSO link provides high bandwidth solution to the last mile access bottleneck. However, for terrestrial communication systems, the performance of these links is severely degraded from atmospheric loss mainly due to fog, rain and snow. So, a continuous availability of the link is always a concern. This paper investigates the dreadful weather effects such as rain, fog, snow, and other losses on the transmission performance of FSO systems. The technique of using an array of receivers for improving the performance of FSO links is explored in this paper. It involves the deployment of multiple photo detectors at the receiver end to mitigate effects of various weather conditions. The performance of the proposed system is evaluated in terms of bit error rate, received signal power, Q-factor and height of eye diagram. The influence of various weather conditions of plain and hilly areas are taken into consideration and results are compared with conventional FSO links.

An all optical communication is fast and reliable for next generation information carrying systems. For successful operation of fast data over flexible transmission line is only possible by all optical multiplexer and can serve for network. A 60 Gbps all optical multiplexer using cheap components has been realized and also tested on different speeds of input data streams. For integral and flexible multiplexer, optical semiconductor-based MZI switch taken into consideration. MZI-SOA is used to generate two logical gates outputs such as (AND)(XOR) gate. Multiplexer working is based on SOA nonlinearity properties and optical coupler. XOR logic gate contingent on cross-phase modulation in amplifier and logic AND for four-wave mixing is obtained from cross port and bar port respectively. Simulation is performed and multiplexer is tested for different launched power in tree architecture. System performance indicates that it can work for high speed (60 Gbps) and different data entities.