An obsessed fan has been ordered to stop stalking Star Trek Voyager actress Jeri Ryan after pleading no contest to the charges.

Marlon Esracio Pagtakhan had been harrassing Ryan and her boyfriend Brannon Braga, executive producer of the show.

Ryan is best known for her role as the Borg, Seven of Nine, in the Voyager series.

Pagtakhan was arrested last November after sending threatening e-mails to the pair, along with sexually explicit messages to the actress.

The defendant allegedly threatened Braga with physical harm, and said if he was sent $10,000 he would leave him alone.

Prosecutor Rhonda Saunders said Pagtakhan, 22, will have to stay at least 1,000 yards from Ryan and Braga and keep away from their workplace and public appearances.

The judge at the Los Angeles court also ordered him to undergo psychiatric counselling and to not use computers for his five year probation period.

Ms Saunders said Ryan had been "very frightened" by the ongoing case.

Pagtakhan had previously ignored a restraining order served on him in September.