Alan Thicke's widow, Tanya Callau, is asking a judge to set Alan's kids straight by telling them to shut up on all their allegations that she's a greedy widow who will try to nullify her prenup to get more cash.

Tanya claims Robin Thicke and his brother, Brennan, were not serious at all when they filed legal docs asking a judge to block her from challenging the prenup she signed with their dad.

Tanya says the Thicke brothers know she has no intention of challenging the prenup, even though she signed it without the benefit of legal representation just 4 days before their wedding.

She says this is all about trashing her in the media and wants the judge to see it for what it is ... a baseless concern.

Tanya insists all she wants is what's hers ... a cut of Alan's ranch, a right to live there and chunk of his other assets. 

As we reported ... Robin and Brennan previously filed legal docs claiming Tanya threatened to trash them in the tabloids if she didn't get what she wanted. She called BS ... claiming they just want her out of the picture so they could turn the family ranch into a pot farm.