Frequency-tunable all-optical clock division using semiconductor laser subjected to external optical injection

All-optical time division was obtained in the frequency range from 9.0 GHz to 19.8 GHz. Nonlinear dynamics of a Fabry-Perot laser diode subjected to external optical injection is applied for all-optical clock division. The research results indicate that semiconductor laser subjected to external light injection performs period-one oscillation. We obtain the clock division of the signal pulses when the second harmonic frequency of the period-one oscillation approaches the repetition rate of the signal pulse, and the second harmonic and the fundamental frequency of the period-one oscillation were locked by the signal pulses simultaneously. Numerical simulation was performed on the all-optical time division with signal pulse injection using the rate equation of the semiconductor laser. The simulation result is in good agreement with the experiment. Phase noise level of the divided clock is observed to be smaller than - 90 dBc/Hz over a frequency detuning range of 1.5 GHz by changing the repetition rate of signal pulses under the fixed wavelength detuning value and input signal pulse power.