| Optical systems designed to operate at near-infrared wavelengths—specifically telecommunication wavelengths—have received considerable interest over the last two decades. This thesis investigates the fabrication of a new class of near-infrared single and angularly-multiplexed volume transmission gratings by exposure at 514.5 nm in a thick holographic photopolymer for spectrally-shifted playback at 1550 nm. Particular emphasis is placed on the novel development of multiplexed holograms optimized as the switching mechanism in a conceptual 1 × N fiber-based optical switch. All gratings are designed for, and recorded in, 200-, 300-, and 500-μm thick formats of an experimental ULSH-500 photopolymer (Aprilis, Inc.).; General recording principles and characteristics of self-processing holographic photopolymers are detailed, and their benefits and limitations are identified. Analysis of ULSH-500 photopolymer shows a highly transparent medium with negli gible absorption from 500–1600 nm. Theoretical design and verification for near-infrared holographic gratings is realized through rigorous coupled-wave analysis (RCWA). A description of RCWA for single and superimposed phase profiles is provided for TE and TM polarizations.; The design, fabrication, and analysis of single, sequentially-multiplexed, and simultaneously-multiplexed holographic gratings are explored in detail. Optimized grating parameters and laboratory procedures are developed to address experimental complexities associated with the spectral shift between exposure and playback. Complications include phase profile overmodulation, real-time effects during exposure, and coupling between previously-recorded phase profiles and subsequently-multiplexed holograms. A diffraction efficiency of 96% at 1550 nm is reported for a single grating developed to saturation in a 200-μm thick sample. Peak diffraction efficiencies of 81.0%, 78.6%, and 65.9% are achieved for three sequentially-multiplexed gratings recorded co-locationally in a 300-μm thick medium. Limitations to grating development include monomer depletion, polymer hardening, secondary grating formation, and spurious grating formation. Experimental results suggest the potential for low-loss, multi-function, near-infrared volume holographic optical elements. Grating quality, performance, and sensitivity are additionally examined in a 1 × N fiber-based optical switch testbed, and the crosstalk between output ports is shown to be negligible. A conceptual packaging enclosure for an operational 1 × N switch is also provided. |
