All-optical logic gate operating with single wavelength.

We design scalable all-optical logic gates that operate with the same input and output wavelength. We demonstrated the operation by using coupled mode equations, and investigated the impact of input power fluctuations and fabrication errors. We found that a wavelength fluctuation 0.3 times greater than the resonant wavelength width will degrade the operation of the system. Stronger coupling increases the wavelength tolerance. As regards coupling coefficient fluctuation, we found that the system is error-free when the fabrication precision is better than ± 5 nm. This study provides information on the required input power stability and tolerable fabrication errors of a scalable system, which moves the numerical study closer to practical realization.