1 August 1996 Nonuniform and off-axis structures for photorefractive waveguides in lithium niobate
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Optical Engineering, 35(8), (1996). doi:10.1117/1.600823
Photorefractive waveguides that are optically modifiable can be used as the adaptive interconnection channels for optical neural networks. We investigate experimentally a refined fabrication method for the photorefractive waveguides in a lithium niobate crystal. The experimental results show that nonuniform illumination by a discontinuous movement of the focus can fabricate a better optical waveguide than uniform illumination by a continuous one. The discontinuous movement of the focus reduces the spatial overlap between the successive exposures, and avoids the redistribution of the space-charge density formed previously. This refinement results in a narrower and clearer index distribution of the waveguide. We further show that good waveguides are fabricated if the focus is scanned in a particular scanning direction that makes a small angle with the plane perpendicular to the c axis of the crystal.
Osamu Matoba, Kazuyoshi Itoh, Yoshiki Ichioka, "Nonuniform and off-axis structures for photorefractive waveguides in lithium niobate," Optical Engineering 35(8), (1 August 1996). http://dx.doi.org/10.1117/1.600823



Refractive index

Near field optics

Near field

Laser crystals

Optical fabrication

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