Phase asymmetry effect in longitudinal offset coupled resonator optical   waveguides
  We show that the implementation of the longitudinal displacement technique for adjusting the coupling coefficients in microring waveguides is subject to a phase asymmetry effect. This issue is shown to substantially alter the system response in apodized filters and cannot be ignored in the design stage. 
Pedro Chamorro-Posada and F. Javier Fraile-Pel\'aez
physics.optics