Unfortunately, it appears that there is so little Esperanto at universities that even Esperanto courses for which students get academic credit are something to write an article about.
Let me quote the most relevant passage from the 1996 paper Esperanto Studies: An Overview:
In Hungary, an important Department of Esperanto has functioned since 1966 in the University of Budapest; while the primary focus has been on the preparation of teachers of the language, the Department has also served as a center for general interlinguistics, particularly under its founder and long-time director István Szerdahelyi (cf. Szerdahelyi 1980). In Poland, the Catholic University of Lublin possesses a major research library and has long been a center for Esperanto studies (Wojtakowski 1979) [...] While such activity has diminished in the recent wave of economic and political change, the strength and depth of this intellectual tradition make a resurgence in the longer term seem likely.
I have been unable to confirm that Esperanto is still taught and researched at Eötvös Loránd University in Budapest. Also, it appears that the Esperanto-related activities in Lublin at some point moved from the Catholic University to the Polytechnical University, and then ceased. (In Hungary, and to a lesser extent in Poland, Esperanto doesn't fit into the current political climate anyway.)
I could not find any university that looks like an obvious choice for you. If I were you, I would try to get hold of issues of the academic journal "Language Problems and Language Planning" (or a comparable one - I am merely mentioning this one because I found some apparently relevant articles there behind a paywall), look for relevant authors there and ask them. (E.g. Sabine Fiedler of Leipzig University published about her Esperanto courses there in 2007/2008.)
Or just study a rare combination of relevant fields and then start researching in this area. E.g., if you could study linguistics, sociology and Romance literature, this would probably give you a perfect foundation. Funding problems may prevent the execution of such a plan, but you could be lucky and find European Union programmes that will throw money at this kind of research if you frame it correctly.