A novel two-channel all-fiber acousto-optic modulator is fabricated.The coupled mode equations based on the interaction of multi-channel surface acoustic waves(SAW)and the guided optical wave(GOW)in fiber are put forward and their solutions are derived.The all-fiber acousto-optic modulator is composed of two-channel SAW device and single mode fiber.Single mode fiber is imbedded into the surface acoustic wave device and the GOW in fiber is modulated by surface acoustic waves which have different center frequ...