Abstract
In this study, to reduce the leaky surface acoustic wave (LSAW) attenuation, a layered structure of air/bulk LiNbO3(LN) layer/elastically softened LN substrate which can be fabricated by a reverse proton exchange (RPE) process was applied to 10° Y-X LN with a larger coupling factor. First, the LSAW attenuation on a structure of air/bulk LN/modified LN was calculated when all material constants of the buried proton exchange (PE) layer were taken into consideration. It was found that the condition in which the attenuation decreases as compared with the bulk value exists for the free and metallized surfaces. Next, the LSAW propagation properties were measured using IDT pairs with 3.6μm wavelength on 10°Y-X LN with the RPE layer and the buried PE layer. The propagation loss PL for the metallized surface was decreased by carrying out the RPE process from 0.44dB/λ of a virgin wafer to 0.01dB/λ. The decrease in PL for the shorted grating was also observed.
