The Gotland Class sub leased to US.
An instructor for Collins Class cryptologic systems explains his job.
---For the latest on this issue see June 11, 2014’s Australia's Future Submarine - Swedish vs German Claims http://gentleseas.blogspot.com.au/2014/06/australias-future-submarine-swedish-vs.html . It is unclear whether Germany or Sweden hold the strongest intellectual property rights to the Stirling AIP.
With all the controversy of Saab, TKMS (and related HDW) in the news its timely to recall Sweden's submarine export activity since the 1980s. The article below of July 23, 2013 is from the Nuclear Threat Intiative (NTI) http://www.nti.org/analysis/articles/sweden-submarine-import-and-export-behavior/ :