What is a fiber optic loopback?

A fiber optic loopback is a device designed to connect the transmitting and receiving ends of a communication link, effectively allowing the output signal from a transmitter to be redirected back into the same device's receiver. This functionality is essential for testing and troubleshooting fiber optic networks, as it allows technicians to verify that the transmission mechanisms are working properly without needing external connections or equipment. By creating this direct connection, the loopback confirms that data sent from the transmitter is successfully received back, thereby validating the integrity of the fiber optics and associated equipment.

The other options describe functions that are not the primary purpose of a loopback. Increasing signal strength is typically achieved through amplification, which is not the role of a loopback device. Routing data involves directing data packets through a network, a separate function that does not pertain to the direct feedback provided by a loopback. An error detection tool might identify problems within a signal, but it does not perform the same function of connecting transmitters and receivers as the loopback does.