Fundamental lower size limit in wavelength selecting structures

The fundamental lower size limit in wavelength selecting structures is explored with the aid of the Heisenberg uncertainty principle. The analysis shows that for a given wavelength selectivity resonating structures with optical feedback have the smallest dimensions. Experimental results obtained with integrated optics microring resonators (Q ~ 3.4 x 10^4) confirm the analysis. In addition, a discussion is given on the validity of the uncertainty principle in terms of hidden variables or restricted knowledge on the system in question.