摘要 |
An optical performance monitoring system includes a four-port tap coupling a tunable optical filter to a light detector. The four-port tap is configured as an optical tap and an optical splitter combined into a single optical element, where the optical tap directs a portion of an optical signal from an optical fiber to the tunable optical filter, and the optical splitter directs the optical signal from the tunable optical filter to the light detector. The optical performance monitoring system may employ tunable optical filters as a double-duty tunable filter or a double-pass tunable filter. As a double-duty tunable filter, optical signals to be monitored are passed through the tunable filter in opposite directions. As a double-pass tunable filter, a reflecting element is arranged on the output side of the tunable filter so that a filtered optical signal can be fed back into the tunable filter.
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