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Acoustic birefringence suppression in a fiber acoustic grating employing solid-core photonic crystal fiber with hexagonal air-hole array cladding

Abstract. An acoustic birefringence suppression scheme for acoustic fiber gratings has been proposed and experimentally demonstrated. Experimental observation of the transmission characteristics of the single-mode-fiber-based (SMF-based) acoustic grating confirms that introduction of one segment of solid-core photonic crystal fiber (PCF) with air-hole array in the cladding region helps to eradicate resonance peak splitting induced by acoustic birefringence, which has been explained by our theoretical analysis from the acoustic wave modulation method and fiber cross-section structure. Moreover, experimental results indicate that the introduction of the solid-core PCF does not have a considerable impact on the frequency dependence of resonance wavelength for the SMF-based acoustic fiber grating, which ensures the performances of the PCF-assisted SMF-based acousto-optic tunable filter for practical applications.