Fault Tolerant All-optical Router with Photorefractive All-optical Switch

摘要

We propose a new type of the fault tolerant all-optical router (FTAR) by using an all-optical switch with photorefractive two-wave mixing. FTAR can detect a cutoff of a main transmitting line and automatically reroute a signal beam from the main line to a backup line. These functions can increase communication reliability of optical wireless. FTAR is composed of only all-optical devices without any electronic devices or any mechanical operations. In the new type of FTAR, the routing of the signal beam is controlled by a control beam transmitting on the main line from a different light source at a receiver in the opposite direction with the signal beam. Compared with the previous type of FTAR composed of two photorefractive crystals, the new configuration offers the simplification of the construction and high transmission efficiency of the signal beam. In this report, we experiment on the FTAR by using a BaTiO_3 and Ar~+ laser whose wavelength is 514.5nm, and confirm the fundamental function of FTAR. We give comparison of the result with the numerical analysis. We also analyze the dependence of the switching time on the input beam intensity of the crystal by a numerical analysis and an experiment.