Graphene oxide multilayer structures for polarisation selection and other functionalities in planar waveguide based integrated photonics

We have demonstrated a waveguide polariser with high extinction ratio on a polymer optical waveguide coated with multi-layer graphene oxide `paper'. Coating was carried out using the drop-casting technique and a concentrated solution of graphene oxide flakes. For an appropriate thickness of graphene oxide, an extinction ratio of approaching 40 dB was measured at 1590 nm, with a variation of only 4.5 dB across the wavelength range from 1530 nm to 1630 nm. This result was achieved for a coated region propagation length of approximately one millimetre. The strongly polarisation dependent propagation loss demonstrated is attributable to the anisotropy of the complex refractive index of graphene oxide paper.