BACKGROUND OF INVENTION
This invention relates generally to optical fibers, optical devices, electronic devices and optoelectronic devices and in particular relates to fiber materials selection, fiber structure design, and fiber drawing techniques for producing a fiber with desired functionality.
A combination of conducting, semiconducting, and insulating materials in well-defined geometries, prescribed micro- and nano-scale dimensions, and with intimate interfaces is essential for the realization of virtually all modern electronic and optoelectronic devices. Historically, such devices are fabricated using a variety of elaborate microfabrication technologies that employ wafer-based processing. The many wafer-based processing techniques currently available enable the combination of certain conducting, semiconducting, and insulating materials in small feature sizes and high device packing densities. But in general, microfabrication techniques are restricted to planar geometries and planar conformality and limited device extent and/or materials coverage area. Microfabricated devices and systems also in general require packaging and typically necessitate very large capital expenditures.
Conversely, modern preform-based optical fiber production techniques can yield extended lengths of material and enable well-controlled geometries and transport characteristics over such extended lengths. In further contrast to wafer-based processing, fiber preform drawing techniques are in general less costly and less complicated. But in general, preform-based optical fiber production has been restricted to large fiber feature dimensions and a relatively small class of dielectric materials developed primarily for enabling optical transmission. A wide range of applications therefore remain to be addressed due to the limitations of both conventional fiber preform-based drawing technologies and conventional microfabrication technologies.
SUMMARY OF THE INVENTION
The invention provides fiber configurations and manufacturing processes that enable optical detection as well as imaging with a single fiber, a woven mat, grid, fabric, or web of fibers, or multiple arrangements of such. The optical fiber photodetector of the invention includes a photoconductive element, such as a semiconducting element, having a fiber length. The semiconducting element can be characterized as a non-composite material in at least one fiber direction. At least one pair of conducting electrodes is in contact with the semiconducting element along the fiber length, and an insulator is provided along the fiber length. An optical resonator can be disposed along the fiber length and along a path of illumination to the semiconducting element. The resonator is dimensioned to substantially reflect all illumination wavelengths except for a prescribed range of wavelengths transmitted to the semiconducting element.
The fiber photodetector can be arranged in a photodetecting fiber grid having a plurality of rows of fiber photodetectors and a plurality of columns of fiber photodetectors. Each fiber photodetector is connected to a sensing circuit for detecting fiber grid coordinates of illumination incident on the fiber grid. Similarly, the fiber photodetector can be arranged in a photodetecting fiber fabric having a plurality of fiber photodetectors woven together, with each fiber photodetector connected to a sensing circuit for detecting illumination incident on the fiber fabric.
The fiber photodetector configurations of the invention provide the ability to interface of materials with widely disparate electrical and optical properties in a fiber while achieving submicron-scale features and arbitrary geometries over extended fiber lengths. Thus is provided by the invention the ability to produce a wide range of optoelectronic functionality at fiber-optic length scales and cost. Other features and advantages of the invention will be apparent from the following description and accompanying figures, and from the claims.
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