A novel proposal for ultra-fast all optical half subtractor based on nonlinear ring resonators

Optical half subtractors are required for designing any optical computation system. Operation speed and the on/off contrast ratios are very important characteristics for any optical logic device. A novel structure composed of three nonlinear ring resonators and some optical waveguides are used for designing for the proposed half subtractor with improved operation speed and on/off contrast ratio. The simulation results show that the rise time for this structure is 1.5 ps. Also the on/off contrast ratios for B and D are 13.7 dB and 14.5 dB respectively.