John Stamos fired off a scathing letter to the judge who sentenced a couple for extorting him -- saying "lying and inventing stories" was their only strategy in court.
TMZ obtained a copy of the letter -- which was read aloud today during the sentencing of Allison Coss and Scott Sippola -- Stamos asked the judge to make an example of the couple ... "This is an opportunity to send a public message that extortion and perjury will not be tolerated."
Stamos added, "They were caught turning the courtroom into a celebrity bashing circus. I was forced to watch the defendant slander me at trial with impunity."
John asked the court for $15,000 for attorney's fees, but the judge shot him down.
Coss and Sippola were sentenced today to four years in prison.