I know it's an old question, but this worked for me in a similar situation on my site. You can use CSS for this.
transition: opacity 1s ease;
-webkit-transition: opacity 1s ease;
Hope this helps someone ...
I'm new at magento 2, and had same challenge.. after hours and hours of searching, what worked for me was..
1 - Download owl-carousel2 js source code to
2 - Add jquery 3.x source code at (because owl-carousel2 compability)