Surface operating photonic devices based on 2D photonic crystal: toward 2.5 dimensional microphotonics

Photonic devices based on 2D PCs have so far been principally targeted at operation in a wave-guided configuration and at providing the basic building blocks for Photonic Integration. The problem of optical losses, which are considered as hindering the operation of 2D photonic integrated circuits based on 2D PC, can be approached from a completely different perspective: instead of attempting to confine the light entirely within waveguide structures, the 2D structures can be deliberately opened to the third space dimension by controlling the coupling between wave-guided and radiation modes. It is shown in this paper that interaction of radiative and guided modes through a photonic crystal, especially under conditions where the later correspond to extrema, of the dispersion characteristics of the photonic crystal, results in resonance phenomena which can be used practically for the development of new classes of devices, e.g. combining photonic crystal and MOEMS (Micro Opto Electro Mechanical Systems) structures. We present here the general trends for designing and fabricating PC-MOEMS structures and first experimental results on demonstrators which are now under investigations in our group.