100% efficient narrow-band acoustooptic tunable reflector using fiber Bragg grating

This paper reports a 100% efficient Bragg-grating-based acoustooptic superlattice modulator in a fiber whose diameter is reduced by HF etching. The acoustically induced reflections, which appear on both sides of the Bragg stop-band, are tunable by altering the acoustic frequency, and have bandwidths corresponding to weak versions of the permanent Bragg grating. These unique properties may lead to important applications in, e.g., reconfigurable wavelength division multiplexing, Q-switching, amplitude modulation, and frequency shifting.