Characterisation of an optical clock recovery method based on a mode-locked laser diode using spectrographic pulse measurement

As channels rates in optical networks are expected to exceed 100Gb/s in the near future, new optical techniques for clock recovery will have to be developed for optical regeneration. This paper describes an optical clock recovery method based on a mode-locked laser diode. Experimental results show that a 42GHz high quality optical clock can be retrieved from a 170Gb/s OTDM data signal. Chirp transfer between the incident signal and the recovered clock signal is investigated using the SHG-FROG method. Results demonstrate that this clock recovery technique is invariant to input dispersion varying between ±75ps/nm, making it ideal for use in 3R regenerators.