All-Optical RZ-to-NRZ Format Conversion with a Tunable Fibre Based Delay Interferometer

All-optical format conversion from return-to-zero (RZ) to non-return-to-zero (NRZ) is demonstrated with temperature-controlled all-fibre delay interferometer (DI) at 20Gb/s. The operation principle is theoretical analysed with the help of numerical simulation and spectra analysis. Theoretical analysis results are consistent well with the experimental results. The format conversion can be achieved with power penalty of 0.54dB and with output extinction ratio 20dB.