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Theoretical characterisation and practical implementation of optical fibre PPM self synchronisation sequences

A novel technique for estimating the optical fibre PPM frame phase and eliminating the pattern dependent jitter is proposed while practical implementations and a mathematical characterisation for the technique are reported. Use is made of naturally occurring sequences thus avoiding the sensitivity and bit rate penalties associated with the previous methods. Tracking additional sequences is demonstrated and shown to be beneficial resulting in a frame rate discrete component enhancement of 10.8 dB and timing variance reduction from 12 × 10−3rad2 to 3.6 × 10−3rod2. Utilising the systematic jitter rejection method proposed resulted in a measured timing variance reduction from 3.6 × 10−3rad2 to 4.2 × 10−5rod2. The limit is imposed by the PLL performance while good correlation is depicted with the theoretical model.