Tunable or pulsed fiber lasers based on all-fiber acousto-optic band pass filters

GUZMÁN-CHAVEZ, ANA DINORA; BELTRAN-PEREZ, GEORGINA; CUADRADO LABORDE, CHRISTIAN; DIEZ, ANTONIO; CRUZ, JOSE LUIS; ANDRES BOU, MIGUEL

Calgary

Workshop; 21th International Laser Physics Workshop LPHYS´12; 2012

University of Calgary

There are many applications that require tunable and dynamic band pass filters (T&DBPF).All-fiber T&D-BPF are particularly useful for the development of tunable laser sources [1]. Core mode blockers (CMB), based on arc discharges, can be fabricated with simple, flexible, and reproducible technique [2,3]. In this work, we report the characterization of an all-fiber acousto-optic T&D-BPF that is composed of a CMB located at the midpoint of the acoustic interaction length. The CMB was produced by H2-loading a Ge-B fiber for fifteen days at 30 bar and then exposed to local electric-arc discharges. The extinction ratio of the core mode produced by the CMB was -36.4 dB at around 1550 nm. When a flexural acoustic wave of about 1.3 MHz propagates along the fiber, then a series of transmission bands can be observed which correspond to the coupling between the fundamental core mode and different cladding modes. The filter can be controlled dynamically by changing the amplitude and the frequency of the acoustic wave. Thus, changing the acoustic frequency makes the filter tunable, while the amplitude of the acoustic wave control the transmittance of the filter.