In-line two-stage erbium doped fiber amplifier system with in-band telemetry channel

摘要

The present invention is an in-line multi-stage erbium doped fiber amplifier system for use in fiber optic communication systems. The system comprises two cascaded erbium doped fiber amplifiers (12), (14) separated by an drop/add device (20) for filtering out the amplifier spontaneous emission noise and the existing telemetry channel and for adding a new telemetry channel before the second amplifier (14). The invention also provides a method for providing a telemetry signal to in-line erbium doped fiber amplifier sites without affecting the signal capacity of the system, and also provides a method for monitoring the performance of a link in an optical fiber communication system.