Photonic crystal structures bear the promise of confining light to structure sizes comparable to the optical wavelength and hence enabling micro optical devices with extremely small footprint. Nonlinear optical (NLO) polymers with large Pockels coefficients have the potential to achieve electro-optic modulators at very low driving voltages. Hence, incorporating photonic crystal structures in NLO polymers is an interesting approach to enable light manipulation on very compact dimensions. However, the comparatively low dielectric contrast of polymers poses limits on the light confinement and performance of devices made in such a material system. In this chapter polymer based photonic crystals are investigated and the maximum achievable quality factors of microcavities in low refractive index contrast materials are evaluated. The photonic bandgap properties of polymer slab waveguide based photonic crystals are described and experimentally confirmed. Different types of microcavities are studied including H1 and L3 cavities, as well as double and multistep heterostructures.
