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Title: Fault-compensated free-space holographic interconnects using FLC spacial light modulators
Author: Smith, Patrick
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1999
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Free-space optical interconnection offers a promising solution to the data bottleneck problems encountered in current computing machinery. Hybrid systems which use electronic processing and optical data connections could alleviate future restrictions on bandwidth. Spatial light modulators (SLMs) are a key part of the input interface between electronic and optical data transfer. The ferroelectric liquid crystal over silicon SLM is a reflective amplitude- or phase-modulation device that has been pioneered at Edinburgh University. The fabrication of such devices still involves delicate manual steps, in part due to the poorly-understood nature of the FLC material. The exacting tolerances involved lead to characteristic error patterns in finished devices, which affect performance in quantifiable ways. One of the most effective ways that the liquid crystal SLM can be used as a data switch is by phase holography, whereby a binary phase pattern on the SLM causes a convolution of input light with the Fourier transform of the binary pattern upon passage through a lens. SLM faults can affect this operation in subtle ways by causing phase errors and contrast loss in the modulation. This is shown using a matrix treatment of birefringence and the output of modified hologram design software. Moreover, the design algorithm can compensate somewhat for the faults in a given SLM by adjusting the phase mask to suit. In a process analogous to adaptive optical techniques, some of the losses can be recovered. This may allow systems to function tolerably even with imperfect modulator devices. Results are presented which show that it is possible to design phase masks to minimize losses due to typical SLM defects. Cell thickness profiles are captured and used to create fault-compensated phase masks.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available