Measurement of Long-Range Surface Plasmon-Polariton devices in Cytop

Long-range surface plasmon-polariton (LRSPP) waveguide structures fabricated of gold stripes (5 mu m wide and 35 nm thick) embedded in CYTOP were characterized. TM polarized 1310 nm light emerging from a polarisation-maintaining optical fibre was injected into the structures via butt-coupling and the output light was measured so that the loss could be calculated. Cutback measurements were carried out on straight waveguides so as to determine their attenuation as well as the butt-coupling loss per facet. Various other passive elements were also characterized. The results were compared with theoretical expectations and errors are surmised to be caused by fabrication imperfections. Thermo-optic modulation measurements were also carried out on straight waveguides. These elements are of interest for biosensors, where propagation through an aqueous solution (having an index of refraction very close to that of Cytop) is necessary.