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All-optical phase and amplitude regenerator for next-generation telecommunications systems


Fibre-optic communications systems have traditionally carried data using binary (on−off) encoding of the light amplitude. However, next-generation systems will use both the amplitude and phase of the optical carrier to achieve higher spectral efficiencies and thus higher overall data capacities1,2. Although this approach requires highly complex transmitters and receivers, the increased capacity and many further practical benefits that accrue from a full knowledge of the amplitude and phase of the optical field3 more than outweigh this additional hardware complexity and can greatly simplify optical network design. However, use of the complex optical field gives rise to a new dominant limitation to system performance—nonlinear phase noise4,5. Developing a device to remove this noise is therefore of great technical importance. Here, we report the development of the first practical (‘black-box’) all-optical regenerator capable of removing both phase and amplitude noise from binary phase-encoded optical communications signals.

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Figure 1: Operation of phase-insensitive and phase-sensitive amplifiers.
Figure 2: Experimental set-up.
Figure 3: Demodulated eye diagrams after balanced detection and differential constellation diagrams (showing bit-to-bit phase changes) measured at 10 Gbit s−1.
Figure 4: BER curves and corresponding eye diagrams.


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This research has received funding from the European Communities Seventh Framework Programme FP/2007-2013 under grant agreements 224547 (PHASORS) and 216863 (BONE), and Science Foundation Ireland under grant agreement 06/IN/1969.

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R.S., F.P. and J.K. contributed equally to this work. R.S., F.P. and J.K. designed, built and accessed the regenerator. R.S., F.P., J.K., R.W., S.S. and A.D.E. contributed to the design and implementation of the carrier recovery unit. C.L., M.S. and P.A.A. built and performed constellation analysis. L.G.-N., D.J., S.H. and S.D. took part in various stages of the design, fabrication and characterization of the highly nonlinear fibres. R.P. and J.O. manufactured the semiconductor slave laser. A.B. contributed to theoretical analysis. P.A.A., A.D.E., L.G.N., J.O., D.S. and P.P. co-managed the work. D.J.R. provided overall technical leadership for the research.

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Correspondence to Radan Slavík.

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Slavík, R., Parmigiani, F., Kakande, J. et al. All-optical phase and amplitude regenerator for next-generation telecommunications systems. Nature Photon 4, 690–695 (2010).

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