Control of dispersion in photonic crystal waveguides using group   symmetry theory
  We demonstrate dispersion tailoring by coupling the even and the odd modes in a line-defect photonic crystal waveguide. Coupling is determined ab-initio using group theory analysis, rather than by trial and error optimisation of the design parameters. A family of dispersion curves is generated by controlling a single geometrical parameter. This concept is demonstrated experimentally on 1.5mm-long waveguides with very good agreement with theory. 
Pierre Colman, Sylvain Combri\'e, Ga\"elle Lehoucq, Alfredo De Rossi
physics.optics