Acousto-optic interaction in biconical tapered fibers: shaping of the stopbands

Gustavo Ramírez-Meléndez; Miguel Ángel Bello-Jiménez; Christian A. Cuadrado-Laborde; Antonio Díez; José Luis Cruz Muñoz; Amparo Rodríguez Cobos; Raúl E. Balderas-Navarro; Miguel V. Andrés Bou
Opt. Eng. 55(3) 036105 doi: 10.1117/1.OE.55.3.036105 Published in: Optical Engineering Volume 55, Issue 3, 2016.


The effect of a gradual reduction of the fiber diameter on the acousto-optic (AO) interaction is reported. The experimental and theoretical study of the intermodal coupling induced by a flexural acoustic wave in a biconical tapered fiber shows that it is possible to shape the transmission spectrum, for example, substantially broadening the bandwidth of the resonant couplings. The geometry of the taper transitions can be regarded as an extra degree of freedom to design the AO devices. Optical bandwidths above 45 nm are reported in a tapered fiber with a gradual reduction of the fiber down to 70 μm diameter. The effect of including long taper transition is also reported in a double-tapered structure. A flat attenuation response is reported with 3-dB stopband bandwidth of 34 nm.