During the DARPA SCENICC program, J. Ford, et al., demonstrated that CFBs provide a compelling route to compact, wide angle imagers. Monocentric lenses readily provide diffraction-limited images over wide field but onto a hemispherically curved image surface. They demonstrated visible CFBs can be tapered, cut and polished to relay curved images to flat sensors. We have shown that this provides a volumetric imaging efficiency a hundredfold larger than bulk optics can produce; a hundred times the resolution in the same volume or a hundred times less volume for the same resolution. Ford's work leveraged commercial fiber bundles available for the visible spectrum based on silica. We have developed hybrid fiber bundles using step-index confinement between chalcogenide glass cores and polymer cladding with high index-contrast. The high contrast is necessary to provide tight confinement to the high-index As-Se core with minimal crosstalk between closely spaced cores. Tight confinement also minimizes absorption losses in the PEI polymer cladding. The high contrast of this system also provides a large NA to optimize coupling into the CFB from fast lenses. We introduce disorder into the core radius as a mechanism to further decouple adjacent cores, reduce crosstalk and increase fill-factor. We present coupled-mode theory, modal crosstalk superposition, and finite-element modelling to quantify coupling losses and crosstalk as a function of geometry and disorder. We fabricated preforms, drew small fiber bundles and characterized optical properties of the bundles to aid scale-up to megapixel MWIR CFBs.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:honorstheses-2014 |
| Date | 01 January 2021 |
| Creators | Lopez-Zelaya, Cesar A |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Honors Undergraduate Theses |
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