Tunable filter based on cavity electro-optic modulation for DWDM applications

In this paper the authors have demonstrated the feasibility and the realization of a wavelength tunable filter with an electro-optic modulation effect realized on diffused Ti:LiNbO3 waveguide. The two reflectors of the cavity consist in two Bragg׳s mirrors of identical period Λ=1.81μm and whose total number N=140. Both mirrors have been engraved using the Focused Ion Beam technique up to the depths l1=l2=2.7μm separated by a distance of lc=500μm. We obtained thanks to electro-optic modulation effect a tunable shift whose value is 0.67 nm in a free spectral range FSR=1.59 nm for a voltage variation up to 60 V. This designed and realized probe will find many DWDM (Dense Wavelength Division Multiplexing) applications.