Optical clock recovery and clock division at 20 Gb/s using a tunable semiconductor fiber ring laser

Optical clock recovery and clock division is demonstrated from a pseudo-data pattern at 20 Gb/s, using a semiconductor optical amplifier fibre ring laser. The ring laser is capable of generating 4.7 ps pulses at 20 GHz repetition rate and less than 3 ps pulses at the divided clock frequencies of 10 and 5 GHz, over a 16 nm tuning range. The effect of the input data pattern on the recovered clock signal is investigated. The extinction ratio of the recovered clock signal to the clock sub-harmonics was found to be as high as 40 dB despite the long series of consecutive zeros of input pattern. (C) 2003 Elsevier Science B.V. All rights reserved.