FTTx是「Fiber To The x」的缩写，意谓「光纤到x」，为各种光纤通信网络的总称，其中x代表光纤线路的目的地。

依目的地的不同，常见的FTTx有以下数类：

Fiber to the x (FTTX) is a generic term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications. As fiber optic cables are able to carry much more data than copper cables, especially over long distances, copper telephone networks built in the 20th century are being replaced by fiber.