مدل سازی و تجزیه و تحلیل عملکرد صوری از OADM برای سیستم نوری تسهیم هیبریدی -OFDM

In this paper, we demonstrated the transmission performance through simulation for integrated dense wavelength division multiplexing and Optical-OFDM system with OADM including the fiber nonlinearity effect. The effects on transmitted channels, fiber link length, operating optical signal wavelength, optical transmitted signal power, optical signal bandwidth, transmission bit rate, optical received power and bit error rate at the receiving side are observed.

Over the last decade, fiber optic cables have been installed by carriers as the backbone of their interoffice networks, becoming the mainstay of the telecommunications infrastructure [1]. This cutting edge technology when combined with network management systems and add–drop multiplexers enables carriers to adopt optically based transmission optical networks that will meet the next generation of transmitted bandwidth demand at a significantly lower cost than installing new fiber [2]. Wavelength selective optical add/drop filter is required for adding and dropping a particular wavelength division multiplexing (WDM) channel at each subscriber's node in the WDM based optical access networks [2]. In these WDM based optical networks, dense wavelength division multiplexing (DWDM) technology is necessary for maximizing the limited transmission bandwidth. Add/drop filter used in DWDM based optical networks should have a good reflection characteristic, temperature stability, a narrow spectral bandwidth, and a low implementation cost [3]. For those reasons, many researchers have been proposed various technologies for implementation of the add/drop filter. Commercialized optical add/drop filters comprise many optical passive devices such as fiber Bragg grating, thin film interference filter, circulator, and Mach-Zehnder interferometer. Although add/drop filters including those devices have good operating performances, their cost is too expensive to apply for DWDM based optical access network [4]. However, the achievements of transparent networks which will be implemented for the wavelength multiplexing technology (WDM) within the next years should be conserved when introducing OTDM in addition to the WDM technology [5]. This implies the need of additional elements in the network: time domain optical add-/drop multiplexer (TD-OADM). Moreover, 100 Gb/s CO-OFDM transmission over 1000 km has been demonstrated by groups from the University of Melbourne [6], KDDI [7], and NTT [8]. Because CO-OFDM uses digital-to-analog converters (DACs) at the transmitter and also unique pilot subcarrier-based channel and phase estimation, it offers an extremely convenient way to achieve high spectral efficiency transmission through higher order modulation. 64-QAM in single polarization [9] and 16-QAM in dual polarization [10] have been reported, both of which represent record spectral efficiency for single polarization and dual polarization, respectively, using off-the-shelf commercial components. In the present work, we have investigated OADM based on DWDM technology for high speed performance of Optical OFDM communication networks. We have taken in to account the bit error rate for added and dropped channels at different fiber link lengths. As well as we have developed OADM for high speed transmission bit rates and products per channel at different optical signal transmitted power. Moreover we have deeply studied the performance evolution of transmitted and received signal powers at different channels at a specific fiber link length. In this paper a simulation is performed for 12 channel DWDM system integrated with MIMO-Optical OFDM technology. The simulation is carried out using powerful software tools Optsim and MATLAB. After having brief introduction in Section 1, Section 2 covers the DWDM system integrated with MIMO-Optical OFDM technology and describes the channel properties of optical fiber with dispersion compensated fiber. Section 3 deals with numerical results and analysis. In Section 4 the spectral efficiency of presented system is described. Finally, Section 5 concludes the paper.

In a summary, we have demonstrated that the OADMs are the simplest elements to introduce wavelength management capabilities by enabling the selective add and drop of optical channels based on DWDM technology in next generation optical networks. It is observed that the decreased number of transmitted channels, fiber link length, and operating optical signal wavelength, the increased optical transmitted signal power, optical signal bandwidth, and transmission bit rate capacity per all transmitted channels. As well as we have observed that the decreased of both number of transmitted channels and operating optical signal wavelength at the same fiber link length, the increased optical received power and the decreased bit error rate at the receiving side. Moreover the decreased fiber link length at constant of both number of transmitted channels and operating optical signal wavelength, the increased optical received signal power, and the decreased bit error rate at the receiving side