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Width (m)Line fit slope (dB/cm)Propagation Loss, (w) (dB/cm) 50-0.14 0.0500.09 0.032 75-0.12 0.0320.08 0.021 100-0.11 0.0510.07 0.033 Experimental Study of Bend and Propagation Loss in Curved Polymer Channel Waveguides for High Bit-Rate Optical Interconnections Ioannis Papakonstantinou, David R. Selviah and F. Anbal Frnandez Department of Electrical and Electronic Engineering, University College London, UK Photoreceiver mm mm mm Bend Radius R (mm) Normalized waveguide loss P norm1 (dBm) Raw experimental data, P bend has coupling loss due to Fresnel reflections and scattering at the end waveguide surfaces. This loss is calibrated out by subtracting the power of a straight waveguide P str1 to give the normalized power P norm1 as: After this calibration the remaining loss is simply due to the bend and can be subdivided into the following components: Transition loss between straight curved and curved straight waveguide segments Pure bend loss due to the leaky nature of bend modes DC EXPERIMENTS mm mm mm Bend loss P bend (dBm) Bend Radius R (mm) P norm1, is the combination of bend P bend, and propagation loss due to material absorption and scattering of light from the waveguide side walls. Propagation loss is calibrated out by subtracting a line, across all bend radii, fitted only at large R as:, where l bend and l cal are the lengths of the bend and the calibration straight waveguide correspondingly. i.papakonstantinou@ee.ucl.ac.uki.papakonstantinou@ee.ucl.ac.uk, d.selviah@ee.ucl.ac.uk, a.fernandez@ee.ucl.ac.ukd.selviah@ee.ucl.ac.uka.fernandez@ee.ucl.ac.uk AC EXPERIMENTS CONCLUSIONS CW experiments on curved waveguides showed that overall loss in the system reached a minimum between 17.5mm < R < 21mm and increased again for larger radii. Propagation loss at 850nm was found to be 0.09 dB/cm, 0.08 dB/cm and 0.07 dB/cm for the 50m, 75m and 100m waveguides respectively. Narrower waveguides appear to have less propagation loss probably due to weaker scattering at the waveguide side walls. Bend loss is higher for wider waveguides. This is due to the transition loss at the first straight bend waveguides interface. Bend loss minimizes after R > 15mm where it seems to saturate. For w = 50m bend loss