Measurement of optical interference due to multiple optical carriers in subcarrier multiplexing

Optical interference noise was measured with two multilongitudinal mode semiconductor lasers. The results show that optical interference may seriously degrade the performance of a subcarrier multiplexing (SCM) system which uses multiple optical sources. It is shown that under worst-case conditions even a single video channel cannot be transmitted. Therefore, steps need to be taken to minimize or avoid the interference, such as separating the laser wavelengths, for example.<>