The way calibre currently does it is leave it largely up to each user. So what I typically do, for e.g. for translated books is:
Fyodor Dostoevsky, Richard Pevear (translator)
and in author sort
So the general scheme is:
The author field should contain a comma separated list of names. Each name should be the "display name" with an optional role in brackets after the name.
The sort field should be of the format last name; first name of the primary author.