INTERFEROMETRIC NOISE IN LIGHTWAVE SYSTEMS WITH OPTICAL PREAMPLIFIERS

Penalties from multi-path interference in transmission systems employi ng optical preamplifiers have been investigated experimentally as web as theoretically. Calculations of the fraction of errors originating f rom the four possible combinations of received and interfering bit are carried out to identify the dominant cause of the power penalties. Wi th perfect extinction ratio, the penalties from phase noise induced in tensity noise (PIIN) are significant only at moderate levels of relati ve crosstalk (-30 dB to -18 dB), whereas the error floors (infinite pe nalty) are caused by beat noise originating from crosstalk and amplifi ed spontaneous emission and a reduction in extinction ratio. Nonperfec t extinction ratios increases the sensitivity to PIIN.