Crosstalk in a two channel coherent fiber optic FSK system using a semiconductor laser amplifier

Bit-error-rate measurements on a two-channel optical transmission system using a low-reflectivity laser amplifier are presented. The signal lasers are directly frequency-modulated or amplitude-modulated at 1 Gb/s. The crosstalk penalties in an FSK-FSK system are very small and are mainly attributed to the residual small amplitude modulation of the lasers resulting from the direct frequency modulation. The crosstalk in an ASK-FSK system is considerably larger.<
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