We report a bandwidth variation technique in an acousto-optic filter. Utilizing the adiabatic conversion in both optical and acoustic modes, we obtain a novel hybrid waveguide composed of serial concatenation of single-mode fiber (SMF) and two-mode hollow optical fiber (HOF). On the basis of dissimilarity in the phase-matching conditions and beat-length dispersion in SMF and HOF, the FWHM of the resonant bands is varied from 3.8 to 190 nm near the 1.5-µm region in a single device. Furthermore, we theoretically analyze the acousto-optic coupling among the guided modes in HOF, which shows good agreement with experimental observations.
© 2005 Optical Society of America
Y. Jung, S. B. Lee, Jhang W. Lee, and K. Oh, "Bandwidth control in a hybrid fiber acousto-optic filter," Opt. Lett. 30, 84-86 (2005)