Who was Ali-Ibn-Mahziar al-Ahvazi (al-Ahwazi)?

َAs far as I know, there is the shrine (tomb) of a person whose name is considered as Ali-ibn-Mahziar-al-Ahvazi (علی بن مهزیار الاهوازی) in Ahvaz (Ahwaz) (the capital of Khuzestan province (Iran)). Seemingly he is as a famous Faghih (the jurist) and also a narrator of traditions. I was wondering who he was exactly and which Imam he was contemporary with.