Optical waveguides in crystalline organic semiconductor thin films

Optical waveguiding in a crystalline organic semiconductor, namely, 3,4,9,10 perylenetetracarboxylic dianhydride (PTCDA), has been demonstrated in slab and rib waveguides using both end-fire and grating coupling at λ 1.064 μm. The effective indices of the transverse electric (TE) modes measured by means of grating coupling are in good agreement with theoretical prediction. A very low propagation loss of 2.5 dB/cm in a PTCDA rib waveguide has been determined from measurements of the scattered light intensity from the top surface of the guide.