Proposal and design of an all-optical encoder for digitising radio-over-fibre transceivers

In this paper it is proposed and designed an original all-optical Encoder (o-Encoder) intended, but not exclusively, to be part of future optical digitising radio-over-fibre (o-DRoF) transceiver. It is based on the Semiconductor Laser Amplifier Loop Mirror (SLALOM) configuration exploiting the nonlinearities of a semiconductor optical amplifier (SOA) in cross-switching regime. The proof-of-principle is established using 40-ps RZ control pulses at 2.5 GHz in the C-band. It outputs serially encoded, quantized and amplified optical RZ bits. Computer simulations of the proposed o-Encoder have shown promising results. The proposed device is rather compact, potentially optically integrable and requires much less input optical power (by several orders of magnitude) than other photonic-encoders and can also naturally convert wavelengths in the optical domain.