An optical transmission line switching apparatus relays main signal light input via a main transmission line including at least two transmission lines. When no failure occurs in the main transmission line, a control unit controls an optical switch and an optical switch so that the optical switch and the optical switch are connected to different transmission lines. When a failure occurs in one of the at least two transmission lines, the control unit controls the optical switch and the optical switch so that the optical switch and the optical switch are connected to a transmission line that does not have the failure. When recovery from the failure is completed, the control unit controls the optical switch and the optical switch so that the optical switch and the optical switch are connected to different transmission lines.

An optical transmission line switching apparatus relays main signal light input via a main transmission line including at least two transmission lines. When no failure occurs in the main transmission line, a control unit controls an optical switch and an optical switch so that the optical switch and the optical switch are connected to different transmission lines. When a failure occurs in one of the at least two transmission lines, the control unit controls the optical switch and the optical switch so that the optical switch and the optical switch are connected to a transmission line that does not have the failure. When recovery from the failure is completed, the control unit controls the optical switch and the optical switch so that the optical switch and the optical switch are connected to different transmission lines.

A system and method for providing redundant wired pipe-in-pipe telemetry is described. In one embodiment, a system includes an outer pipe and an inner pipe disposed within the outer pipe. The outer pipe axially supports the inner pipe using a collar of the inner pipe. A first conductive element is coupled to the inner pipe and disposed at least partially within an annulus between the inner pipe and the outer pipe. A second conductive element is disposed within the outer pipe. A wired path controller is coupled to the collar of the inner pipe, and also coupled to the first conductive element and the second conductive element. A connector is coupled to the collar of the inner pipe, which coupled the second conductive element to the wired path controller.