Aluminum Nitride Thin Film Acousto-Optic Modulator based on Single-Phase Unidirectional Transducers

In this work, the design and analysis of high coupling-efficiency chip-scale acoustooptic modulators (AOMs) based on aluminum nitride (AlN) thin film enabled by single-phase unidirectional transducers (SPUDT) are present. Two types of SPUDT are compared and the modulation frequencies are swept by finite element analysis (FEA) in order to achieve the highest acousto-optic modulation efficiency (
$g_{ao}$
) and optical waveguide position are optimized by calculating
$g_{ao}$
for TE
00
and TE
10
optical modes with different structure parameters. The result shows the optimal position of waveguides is in the middle of gap and the
$g_{ao}$
of AOM based on Double SPUDT configuration is slightly higher than that of Bottom Floating SPUDT (BF SPUDT) configuration. These designs open new horizons towards integrating various types of SPUDT and optical devices together on released AlN thin film platform with high performance for numerous advanced chip-scale acoustooptic applications including optical isolator, nonreciprocal modulation.