ICTACT Journal on Communication Technology

Suvarna S. Patil ¹, Bharat S. Chaudhari ², Baojun Li ³

Affiliations
1 Bharati Vidyapeeth University College of Engineering, Pune, IN
2 International Institute of Information Technology, Pune, IN
3 State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou 510275, CN

Abstract

Optical cross-connects are one of the most important components in the dense wavelength division multiplexer based optical networks. The crossconnects suffer from crosstalk due to the different wavelength light path channels during the switching process leading to the deterioration in bit error rate (BER) and hence in the system performance. This paper presents the study of impact of coherent and incoherent crosstalk and power penalty on the optical cross-connects in WDM Networks. The effect of accumulation of coherent crosstalk at different stages of crossconnect has been also investigated and analyzed for the blocking probabilities. Results of coherent and incoherent crosstalk are compared to identify their impact on the working of the cross-connect. The results show that the crosstalk increases with increase in either the number of wavelengths per fiber or the number of input fibers. The result also illustrates decrease in the interference penalty by correlating the crosstalk contributions with each other at the appropriate phase angle. We show that an acceptable blocking probability due to crosstalk is achievable for active wavelengths in the WDM network. The present study can be used to model the possible number of routing stages in such networks.

Keywords

Coherent Crosstalk, Incoherent Crosstalk, Optical Cross-Connects, Blocking Probabilities, Power Penalty.

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Shilpa S. Patil ¹, Bharat S. Chaudhari ¹, Baojun Li ²

Affiliations
1 Department of Electronics and Telecommunication Engineering, Maharashtra Institute of Technology, IN
2 State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, CN

Abstract

In wavelength division multiplexed all optical networks; lightpath establishes a connection between sending and receiving nodes bypassing the electronic processing at intermediate nodes. One of the prime objectives of Routing and Wavelength Assignment (RWA) problem is to maximize the number of connections efficiently by choosing the best routes. Although there are several algorithms available, improving the blocking performance in optical networks and finding optimal solutions for RWA problem has still remained a challenging issue. Wavelength conversion can be helpful in restricting the problem of wavelength continuity constraint but it increases complexity in the network. In this paper, we propose new weight dependent routing and wavelength assignment strategy for all optical networks without use of wavelength converters. Proposed weight function reduces blocking probability significantly, improving the network performance at various load conditions. Further, due to absence of wavelength converters, the cost and complexity of network reduces. Results show that the proposed strategy performs better than earlier reported methods.

Keywords

WDM, Lightpath, RWA, NSFnet, Blocking Probability.

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