Reduction of intersymbol interference by matching a voxel lattice constant and a point spread function shadow in optical systems
Technology is disclosed for improving read accuracy and storage capacity in optical data storage systems. The technology includes writing, with an optical write system, voxels into a voxel lattice having a voxel lattice constant (VLC) of an optical storage medium and reading, with an optical read system, the voxels from the optical storage medium. The optical read system includes optical components that have a point spread function (PSF). The VLC matches a shadow of the PSF either by virtue of the write system setting the VLC to match the shadow of the PSF of the read system or the read system adjusting the optical components to match the shadow of the PSF with the VLC. The system may be tuned by selecting which shadow of the PSF is used for matching with the VLC, the shape of the voxel lattice, the number of bits per voxel, or a combination.
1 . An optical read system, comprising:
a read controller, comprising:
a light source configured to emit a beam, and
a sensor system configured to detect voxels written in an optical storage medium, wherein:
the voxels are written in the optical storage medium in a voxel lattice having a voxel lattice constant representing a distance between neighboring voxels in a layer of the optical storage medium;
a decoder configured to decode the voxels to identify data represented by the voxels; and
an optical read head, comprising:
optical components including one or more lenses; and
a focusing system, wherein:
the optical read head is configured to receive and steer the beam toward the voxels,
the optical components have a point spread function, and
the optical components are configured to match a shadow of the point spread function with the voxel lattice constant.
2 . The optical read system of claim 1 , wherein the focusing system is configured to at least adjust the point spread function to match the shadow of the point spread function with the voxel lattice constant.
3 . The optical read system of claim 2 , wherein to adjust the point spread function, the focusing system is configured to at least modify a numerical aperture of at least one of the one or more lenses.
4 . The optical read system of claim 2 , wherein to adjust the point spread function, the focusing system is configured to at least modify the beam using one of deformable mirrors or spatial light modulators.
5 . The optical read system of claim 2 , wherein to adjust the point spread function, the focusing system is configured to at least modify a wavelength of the beam.
6 . The optical read system of claim 1 , wherein the point spread function comprises at least two shadows, and the optical components are configured to match one shadow of the at least two shadows with the voxel lattice constant.
7 . The optical read system of claim 1 , wherein the voxel lattice comprises one of a rectangular grid and a hexagonal grid.
8 . The optical read system of claim 1 , wherein each voxel of the voxels stores a one-bit symbol.
9 . The optical read system of claim 1 , wherein each voxel of the voxels stores a two-bit symbol.
10 . The optical read system of claim 1 , wherein the voxel lattice constant is between 150 nanometers and 600 nanometers.
11 . An optical write system, comprising:
a write controller, comprising:
a laser configured to emit a beam having a pulse train, and
a modulation system comprising modulators configured to modulate the pulses of the pulse train to encode data in each pulse of the pulse train;
an optical write head, comprising:
optical components including one or more lenses; and
a scanning system configured to use the optical components to direct the beam having the modulated pulses in the pulse train at an optical storage medium to write the data into the optical storage medium,
wherein the optical components are configured to:
write the data into voxels in a voxel lattice having a voxel lattice constant representing a distance between neighboring voxels in a layer of the optical storage medium, and
match the voxel lattice constant with a shadow of a point spread function of a laser read system.
12 . The optical write system of claim 11 , wherein the scanning system is configured to adjust the voxel lattice constant to match the voxel lattice constant with the shadow of the point spread function.
13 . The optical write system of claim 12 , wherein to adjust the voxel lattice constant, the scanning system is configured to instruct movement of the optical write head to write the voxels into the optical storage medium at precise locations corresponding to the adjusted voxel lattice constant.
14 . The optical write system of claim 11 , wherein the point spread function comprises at least two shadows, and the optical components are configured to match the voxel lattice constant with one shadow of the at least two shadows.
15 . The optical write system of claim 11 , wherein the voxel lattice comprises one of a rectangular grid and a hexagonal grid.
16 . The optical write system of claim 11 , wherein the modulation system is configured to modulate each pulse of the pulse train to encode a one-bit symbol in each voxel of the voxels.
17 . The optical write system of claim 11 , wherein the modulation system is configured to modulate each pulse of the pulse train to encode a two-bit symbol in each voxel of the voxels.
18 . The optical write system of claim 11 , wherein the modulation system is configured to amplify each pulse of the pulse train such that each voxel of the voxels fits within a space of the voxel lattice, and the voxel lattice constant is between 150 nanometers and 600 nanometers.
19 . A method, comprising:
encoding, by an optical write drive, data into each pulse of a pulse train emitted from a femtosecond laser;
writing, by the optical write drive, the data into voxels in an optical storage medium, wherein the voxels are written into a voxel lattice having a voxel lattice constant representing a distance between neighboring voxels in a layer of the optical storage medium;
adjusting, by an optical read drive, optical components of the optical read drive to match a shadow of a point spread function with the voxel lattice constant; and
reading, by the optical read drive, the voxels from the optical storage medium after adjusting the optical components.
20 . The method of claim 19 , wherein:
the point spread function comprises at least two shadows; and
the optical read drive adjusts the optical components to match one of the at least two shadows with the voxel lattice constant.