Bharaghlaf is the setting (obviously) of the dark fantasy Bharaghlafi series (A Business of Ferrets; A Parliament of Owls; and -- the current Work In Progress -- An Ambush of Tigers). What may be less obvious is that A Necklace of Fallen Stars in also set in the same world, though outside the Empire, and a couple of centuries before the events in the Bharaghlafi chronicles occur. Another early work (which has never been published, and likely never will be) was set in Kalledann. So I've been "living" in the Bharaghlaf world since the early 1970s. 

The cat books (Cats in Cyberspace; PKP For President) are set in something very like the real world of the Early Days of the Internet. (I'd call them "historical fiction," except that no one else believes that my cats can communicate via email.) Occasionally, I confess to the autobiographical nature of those books: I had Dana's job; the cats were really my cats; but for simplicity's sake, the books get lumped into the fantasy genre. There may be another couple of cat books to come, but they can wait; I do have fans who have been waiting a very long time for more of the Bharaghlafi chronicles, so that's where my energy is at the moment. 

The Hidden Kingdom (and environs) is definitely not in the same world as the Bharaghalfi Empire. I had a lot of fun coming up with something I could tie to our contemporary world, that was different but had enough echoes so that it would be believable that the two main characters could switch places and lives and still find elements of their previous lives and experiences that were of use in a new and very different setting. It was important to me that The Ivory Mask be a complete story, that doesn't need a sequel (or several) to get resolved. Someday, perhaps I'll go back to that world; but there are no plans for that at the moment. 

I invented the world of the Loom in order to have a place, without a lot of inward, known-only-to-the-author backstory, where I could set a duology. There were two nonnegotiable aspects for the story: it was a pair of books, not a series; and the character from here who went there wasn't going to get any extra, author provided quick explanation that allowed her effortlessly to acquire the language.