Photonic differentiator employing self-induced optical modulation effect

We propose and demonstrate a sub-gigahertz bandwidth photonic differentiator employing the self-induced optical modulation effect in a silicon-on-insulator micro-ring resonator. The all-passive DIFF is controlled through an all-optical pump-probe scheme. Input Gaussian-like pulses with 7.5ns pulse width are differentiated at high processing accuracy. A semi-analytical model that agrees with the experimental results is also derived. The DIFF’s energy efficiency is higher than 45%, far surpassing all previously reported schemes for sub-gigahertz bandwidth pulses. Our scheme expands the application potential of photonic DIFFs.