Intermodulation distortions of broad-band modulated laser diodes

For modulation frequencies with arbitrary frequency spacing the intermodulation distortions of laser diodes have been investigated both theoretically and experimentally. The second-order distortions only depend on the resulting intermodulation frequency, whereas for the third-order distortions the position of each modulation frequency must be considered. With respect to subcarrier multiplexed (SCM) communication systems, it was found that carriers with large frequency differences can increase the third-order intermodulation distortions up to 15 dB compared to those for closely spaced carriers.<
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