Passive polymer waveguides for interconnection of lightwave components.

摘要

The use of passive polymer waveguides for interconnections in lightwave systems is investigated. We review many of the polymers that are currently being studied and used to make optical waveguides. In all of these waveguide designs and experiments, we used Amoco Ultradel 4212, which is a highly fluorinated polyimide.; The main focus of the research is the development and understanding of the use of passive polymer waveguides in lightwave systems. One of the main problems associated with using passive waveguides made of polymers, as well as other materials, is the coupling between the different components in the system. We have developed a tapered waveguide structure which can be used to aid in the coupling between components with different mode sizes and shapes. The taper contains two guiding layers which transform an optical mode from one shape to another with minimal loss.; In order to gain further understanding of the coupling between different components, a model was developed to calculate the coupling efficiencies between different waveguide components with varying component misalignments. This model was used to analyze the coupling between lasers, polymer waveguides and optical fibers, showing the effect of the different component misalignments. It was found that there is a tradeoff between the coupling efficiency and the alignment tolerance. The optimal waveguide structures, using our material system, were found for laser and fiber coupling.; Using the optimal structure for laser and fiber coupling, a tapered polymer waveguide was designed for increased coupling between the laser and waveguide. The tapered waveguide was analyzed to show the light as it propagates through the taper structure, and also to find the propagation loss in the taper.; Waveguide fabrication using DCM dye-doped 4212 polyimide is described. The channels are defined by ultraviolet (UV) photobleaching using standard photolithography. Waveguides were fabricated and tested. The lateral and vertical misalignments which cause a 3dB drop in the coupling efficiency were measured. These experimental results were compared with theoretically calculated coupling results. Fabry-Perot cavity effects, which occur between the laser and waveguide, were experimentally observed and theoretically analyzed.; We also show an application using passive polymer waveguides together with semiconductor optical amplifiers (SOAs) to make a hybrid optical switch. The passive waveguides route the optical signal, and the SOAs are used to gate and amplify the signal. A comprehensive analysis of the losses in the passive polymer waveguide network is performed, including splitter losses, channel crossings, and channel bends. We use a Monte Carlo analysis to find the coupling losses between the components due to misalignments. We also calculated the maximum number of 2 x 2 and 4 x 4 hybrid switch modules that could be cascaded while maintaining a bit error (BER) of less than 10--9 .; A different fabrication method for passive polymer waveguides was also demonstrated. This fabrication technique, called embossing, uses a master structure which is replicated in a polymer layer. Embossing can be used to make straight waveguides, as well as waveguides for out-of-plane coupling. A mirrored surface can be directly embossed into the waveguide by using a master structure with a 45° surface on one end. The fabrication of various embossed waveguide channels was demonstrated.