"Opposite to" isn't a commonly heard collocation. When you use "opposite" as a noun, you might say one word "is the opposite of" another word; but when "opposite" is used as a preposition of place, it doesn't need another preposition after it. In American English, "across from" is much more commonly used than "opposite" as a preposition of place. Up is the opposite of down. In is the opposite of out. The bank is opposite the Post Office. (British English) The bank is across from the Post Office. (American English)

"opposite opinion" doesn't need "to"

You must also take note of the contetext in which you are using it, opposite to is more formal and academic while opposite is more casual