Although the federal prisons created the concept of the conjugal visit in the first place, they were also the first to axe the idea, too. In California, if you're already married when you go to a state prison, or if you and the inmate have a child with his last name, you can get on the list to wait for an available "family visit" with the inmate, you, and even children. The CDC usually puts a limit on such visits, with a maximum of 43 hours. If you are not already married, you may be wed at the facility, and then AFTER you wait the mandatory 6 mo waiting period, you can then wait for it to be your turn on the waiting list for an available visitation house.
I am not aware of any federal prison, that has conjugal visits, my husband is in Texas and they are not allowed any kinda of conjugal visit or even a special visit. He is just granted regular visits. I have searched all over the net and through the web site of BOP and there is no such law grating us that our married to have alone time with out spouses.