Countering the gain behavior of Erbium Doped Fiber Amplifiers: A cross layer approach

Various methods have been proposed in the literature for improving the quality and throughput performance of optical networks, decreasing the bit error rate as well as avoiding saturation of physical layer components. With the increasing demand for high speed Internet and explosive growth in real time applications over the Internet, it is essential to determine the feasibility of establishing light paths with appropriate quality of service (QoS) using optical switching and networking. Properties of optical fibers, optical switching elements and amplifiers play an important role in supporting end-to-end QoS requirements by ensuring that they operate over the desired operating range. In this paper, simulations are designed that observe the behavior of different wavelengths in optical networks under a variety of situations and determine the quality of signals over different wavelengths. The signal quality depends upon the length of optical fiber and the number of Erbium Doped Fiber Amplifiers (EDFA). The simulation study described here is conducted using the simulation tool Optsim. This study determines that once an EDFA gets saturated, its gain decreases with increasing input level. This behavior of EDFAs can significantly affect signal quality and survivability of a wavelength over the optical long haul network. This simulation study provides a bit error rate (BER) analysis of EDFA when multiple wavelengths arrive at the input of an EDFA. A cross layer optimization approach is proposed that is shown to be effective in mitigating the transient gain behavior of EDFA.