Abstract: A 2×2 fiber-optic switch based on a fused fiber coupler and a magnetic fluid film is presented. Theoretical analysis and experimental results show that the coupler's output powers are changed when refractive index of the external magnetic fluid film varies with the magnetic density on the fused coupling zone. Optical switching function can be carried out. The experimental result generally agrees with the theoretical analysis. The isolation ratio of the optical switch is more than 26 dB.

Key words: coupler, isolation ratio, magnetic fluid, optical switch, fiber