40 Gbit/s transmission over 103 km of NDSF using polarisation independent mid-span spectral inversion by four-wave mixing in a semiconductor optical amplifier

40 Gbit/s OTDM transmission over 103 km of standard fibre, is demonstrated for the first time using polarisation-insensitive mid-span spectral inversion. The phase-conjugation is achieved by four-wave mixing in an optimised SOA, using two orthogonally-polarised pumps for polarisation-independence.