Optical transceivers comprising optical loopback circuits are described. The optical transceiver may comprise a housing, which may host a transmitter, a receiver and the optical loopback circuit. The optical loopback circuit may be configured to route at least a portion of a modulated optical signal from the transmitter to the receiver. The optical loopback circuit may comprise tap couplers and/or optical switches. The optical transceiver may be switched between a normal mode and a calibration mode. The optical transceiver may maintain the same fiber connections even when the optical transceiver is switched from one mode to another. The transmitter, the receiver and the optical loopback circuit may be disposed on a common substrate, or on separate substrates.

Systems, methods, and storage media for detecting a security intrusion of a network device are disclosed. Exemplary implementations may include a method involving, in the network device including a processor, monitor a light signal associated with a security enabled port of the network device; and in response to detecting a change in the light signal, initiate a security alert.

Systems, methods, and storage media for detecting a security intrusion of a network device are disclosed. Exemplary implementations may include a method involving, in the network device including a processor, monitor a light signal associated with a security enabled port of the network device; and in response to detecting a change in the light signal, initiate a security alert.

There is provided apparatuses to detect occurrence and location of damages on optical fiber links in advance by converting an optical span in optical network to an interferometry based sensing media. The interferometry based sensing media may enable detection of mechanical perturbation or mechanical vibration occurred on optical fiber links across optical network. The system employed with the interferometry based sensing media can detect occurrence of mechanical perturbation or mechanical vibration as well as discover the location of such event occurred using standard interferometry based sensing techniques.

There is provided apparatuses to detect occurrence and location of damages on optical fiber links in advance by converting an optical span in optical network to an interferometry based sensing media. The interferometry based sensing media may enable detection of mechanical perturbation or mechanical vibration occurred on optical fiber links across optical network. The system employed with the interferometry based sensing media can detect occurrence of mechanical perturbation or mechanical vibration as well as discover the location of such event occurred using standard interferometry based sensing techniques.

There is provided an OTDR receive device, an OTDR system comprising an OTDR receive device and an OTDR method wherein the OTDR unit and the OTDR receive device are to be connected at opposite ends of an optical fiber link under test. The OTDR receive device comprises means for the OTDR system to detect an established connectivity between the OTDR unit and the OTDR receive device via the optical fiber link under test and a status indicator to notify a user of the receive device of the connectivity status and optionally an OTDR measurement status. Connectivity detection allows to check for continuity between the OTDR unit and the OTDR receive device before launching an OTDR measurement. A user of the OTDR unit does not need to communicate with the user of the OTDR receive device to know when to start the acquisition.

There is provided an OTDR receive device, an OTDR system comprising an OTDR receive device and an OTDR method wherein the OTDR unit and the OTDR receive device are to be connected at opposite ends of an optical fiber link under test. The OTDR receive device comprises means for the OTDR system to detect an established connectivity between the OTDR unit and the OTDR receive device via the optical fiber link under test and a status indicator to notify a user of the receive device of the connectivity status and optionally an OTDR measurement status. Connectivity detection allows to check for continuity between the OTDR unit and the OTDR receive device before launching an OTDR measurement. A user of the OTDR unit does not need to communicate with the user of the OTDR receive device to know when to start the acquisition.

Systems, methods, and devices are disclosed for monitoring optical communications between a managed location and a remote location. In particular, an optical signal is transmitted over an optical fiber and passed-through a test device. A portion of the optical signal is filtered from the original optical signal and passed to a monitoring unit. The monitoring unit may instruct one or more switches in the test device to loop the optical signal back toward the managed location. Subsequently, testing and monitoring may be performed at the managed location. The device may provide a test output or may transmit the information to the managed location.

Systems, methods, and devices are disclosed for monitoring optical communications between a managed location and a remote location. In particular, an optical signal is transmitted over an optical fiber and passed-through a test device. A portion of the optical signal is filtered from the original optical signal and passed to a monitoring unit. The monitoring unit may instruct one or more switches in the test device to loop the optical signal back toward the managed location. Subsequently, testing and monitoring may be performed at the managed location. The device may provide a test output or may transmit the information to the managed location.

An indexing system includes an indexing component; a redundant optical path; and a fiber tap arrangement. Multiple indexing components can be daisy-chained together in the indexing system. The redundant optical path is created between any forward port and any rearward port in the network. Multiple redundant optical paths can be created within the network. One or more tap arrangements can be disposed along each redundant optical path. Accordingly, feed signals in a bidirectional indexing environment can be supplied to each drop line along the redundant optical path from either direction without recabling.