Is it possible to use attention layer as a sort of filter of input data before passing it further to the network?

Is it possible to use attention layer as a sort of filter of input data before passing it further to the network? Is it possible to use it to reduce the dimension of the input (similar as PCA, for example - only attention layer would be trained with the network) and therefore reduce the network architecture (for example we can use network which accepts smaller input dimension)? I can't find decisive sources on that matter.