A friend failed to yield while making a right-hand turn onto a freeway entrance to an oncoming police officer on a motorcycle. He was pulled over and given a ticket by that same officer. I thought that if a police officer is involved in an incident that he has to have another officer write the ticket. Is that correct?

No. Your friend pulled in front of him and did not yield. This would be no different if your friend blew a stop sign in front of the cop or blew through a red light or crashed into the back of his cruiser. It makes no difference.

There could be an issue if the same cop had given him 3 previous tickets. In Florida if a cop gave you 3 tickets all in the same day he would have to call out another officer to give you a 4th ticket to avoid harassment problems in court.

There is no reason they can not, write the ticket for a traffic violatoin that they witnessed, that includes one they were in. Since they are the best witness.

But it will depend on the department, some require another officer to come and write it, but he will use what the other officer said, so the ticket will still be wrote.