Fiber optic loop buffer switch incorporating 3R regeneration

In this paper, an all-optical regenerator based, photonic packet switch architecture, which consists of fiber loop for the storage of the contending packets, is proposed. In the loop buffer, the available buffer space may not be fully utilized due to the re-circulation limit (maximum number of re-circulations that data can take before it can be correctly received at the output). The re-circulation limit arises due to the accumulated ASE (amplified spontaneous emission) noise of the optical amplifier and crosstalk of the optical components. This limit can be counteract by placing a pool of regenerators inside the buffer, which regenerates the signal after some fixed number of re-circulations. As optical regenerators are costly devices, hence they should be placed optimally in the buffer. To do so, in this paper an expression is presented to evaluate the minimum number of required regenerators, to be placed optimally in the buffer for different buffer configurations (B) and re-circulation limits (K), such that full buffer capacity can be utilized without any re-circulation constraints. The simulation results in terms of packet loss probability are presented by considering the detrimental effect of re-circulation limits. Finally, advantages gain due to the regenerator placement inside the buffer are shown.