Design and Simulation of 1.28 Tbps Dense Wavelength Division Multiplex System Suitable for Long Haul Backbone

Abstract

Wavelength division multiplex (WDM) system with on/off keying (OOK) modulation and direct detection (DD) is generally simple to implement, less expensive and energy efficient. The determination of the possible design capacity limit, in terms of the bit rate – distance product in WDM – OOK –DD systems is therefore crucial, considering transmitter/receiver simplicity, as well as energy and cost efficiency.

A 32-channel WDM system is designed and simulated over 1000 km fiber length using Optsim commercial simulation software. The standard channel spacing of 0.4 nm was used in the C–band range from 1.5436 to 1.556 nm.

Each channel used the simple non return to zero – on/off keying (NRZ – OOK) modulation format to modulate a continuous wave (CW) laser source at 40 Gbps using an external modulator, while the receiver uses a DD scheme.

It is proposed that the design will be suitable for long haul mobile backbone in a national network, since up to 1.28 Tbps data rates can be transmitted over 1000 km.

A bit rate length product of 1.28 Pbps.km was obtained as the optimum capacity limit in 32 channel dispersion managed WDM – OOK – DD system.