The properties and development of low-loss (<1 dB/cm) graded-index (GRIN) polymer microstructure waveguides (PMSWs) on various substrates, including semiconductors, conductors, insulators, and Ceramics, are described. PMSW films can now be produced, uniformly, over substrate areas exceeding 400 cm2. The polymer materials exhibit wide transmission bandwidths (0.3 to 2.7 μm) and thermal stability characteristics over a large dynamic temperature range ( —100°C to +180°C). Local sensitization techniques have been applied to PMSW films to produce planar, single and multiplexed, holographic gratings. Wavelength division demultiplexing devices and single-wavelength 1-to-N fanout optical interconnects have also been realized. The polymer technology reported is well suited for optical interconnection, signal processing, communication, and sensing applications.