Second-harmonic reflectors on 128 degrees LiNbO3.
In this work, we study theoretically the operation of long surface acoustic wave reflectors, comprising a large number of electrodes, at the fundamental and second harmonic frequencies on the 128 degrees LiNbO3 substrate for various electrode thicknesses and metallization ratios. Numerical simulations utilizing tailored test structures and time gating indicate that the reflectivity of the second-harmonic reflectors can be very high for certain geometries. Furthermore, our simulations suggest that inside the stopband the total losses for the second harmonic are of the same order as those for operation at the fundamental harmonic.
Lehtonen
Saku
S
Materials Physics Laboratory, P.O. Box 2200, FIN 02015 HUT, Finland. saku@focus.hut.fi
Plessky
Victor P
VP
Koskela
Julius
J
Salomaa
Martti M
MM