Summary form only given. The authors contrast the results of work on long (30 cm) YBaCuO microstrip interconnections and short (<10 cm) waveguided optical interconnections. 4000-angstrom YBaCuO films were coevaporated on 1-in2 LaGaO3 substrates and a 30-cm microstrip was patterned by lift-off. Measurements suggest 1) that flux motion does not introduce significant nonlinearites below 76 K, 2) that Jc rather than Hc is the appropriate limit on maximum current density, and 3) that high-performance transmission lines can be achieved if the low surface resistance expected for superconductors is achieved. The authors have also evaluated an alkyl-silicon polymer waveguide material in which the waveguide is defined simply by exposure to deep ultraviolet, requiring no etching or other patterning of the material. Attenuations less than 0.5 dB/cm were measured on 1-cm waveguides, and low loss bends (1-mm radius) and single-plane crossovers were demonstrated. The optical interconnects formed are directly compatible with underlying electronics and optoelectronics and suitable for lengths of up to several centimeters (limited by attenuation).