Ultra-Widely Tunable Acousto-Optic Add-Drop Filter Based on Acoustically-Induced Polarization Conversion of Single Mode Fiber

An ultra-widely tunable acousto-optic add-drop filter is proposed and demonstrated based on the acoustically-induced polarization conversion of cladding-etched single-mode fiber, which covers wavelengths from 1081 nm to 1582 nm with a tuning band larger than 500 nm. The constructed filter has reconfigurable band-pass and band-rejection filtering characteristics, and obtains the advantages of ultra-wide wavelength tuning range, fast tuning speed, simple fabrication and zero frequency shift. It has potential applications in the fields of WDM communication, ultra-wide tunable laser, signal processing, swept-source optical coherence tomography (SS-OCT) and wideband spectroscopy.