The U.S.S. Defiant was outfitted with a Romulan cloaking device for use exclusively in the Gamma Quadrant. Starfleet's agreement with the Romulan military expressly forbade the use of the cloaking device in the Alpha Quadrant.
Unfortunately, that starship and the cloaking technology aboard it was destroyed by the Dominion at the Second Battle of Chin'Toka.
The Pegasus Project was scrapped by Starfleet after the loss of the U.S.S. Pegasus.
So, in the end, no Federation ships have cloaking devices. Even yours.