Microsecond optical - optical switching in a neodymium-doped two-mode fiber.

We report on optically induced optical switching of a 632.8-nm signal in a Nd3+-doped, two-mode fiber based on a nonlinearity resonantly enhanced by the dopant. A fast, 0.38-μs component was observed in the switched signal, which we believe is due to cross relaxation between clustered ions. We demonstrated a 600-kHz switch in a 1.14-m elliptical-core fiber with 0.31 μJ of launched 807-nm pump energy. Information about cluster size and speed of the cross-relaxation process is inferred from the switch dynamics.