Abstract

We recently reported a new type of acoustooptic modulator for optical fiber^1,2 which uses a glass capillary half to provide a semicylindrical contact region between the acoustic transducer and optical fiber. Phase modulation in single-mode fiber and mode coupling in two-mode fiber have been demonstrated. This paper presents an extension of the latter interaction to provide switchable tapping of light propagating in the fundamental mode of a two-mode fiber. Using a 1-GHz acoustic frequency, we observed up to –30-dB tapping of the fundamental mode with a 3-dB bandwidth of 20 MHz. We also discuss the tapping of light in a single-mode fiber via a similar coupling mechanism with low-order cladding modes.

© 1990 Optical Society of America