Wavelength tunable fiber Bragg grating devices based on sputter deposited resistive and piezoelectric coatings*

Abstract

Two all-fiber wavelength tunable devices, one utilizing thermal tuning and a second based on strain tuning, have been produced by combining resistive Ti/Pt and piezoelectric ZnO fiber coatings with fiber Bragg gratings (FBGs). The Ti and Pt coatings with thicknesses of 40 and 300 nm, respectively, were deposited by sequential magnetron sputter deposition. ZnO fiber coatings with a thickness of 18 μm were deposited by dual magnetron reactive sputtering. Joule heating of the Ti/Pt fiber coating was employed for the thermally tunable FBG device, which exhibited a tuning efficiency of 4.1 nm/W. The piezoelectric fiber Bragg grating device allowed for modulated tuning of the FBG wavelength through a strain modulation induced by the piezoelectric ZnO coating. A wavelength modulation amplitude of 0.044 nm was achieved at a driving potential amplitude of 1.26 V and frequency of 15.26 MHz.