Systems and methods for increasing data rate and storage density in 3-dimensional optical data storage media

A focus error signal (FES) subsystem for detecting a light signal from a moving three-dimensional optical information storage medium and generating a FES signal, comprising:

• at least one FES beam splitter receiving the light signal;
• a first FES channel, including at least one first FES lens that receives the light signal from a first output of the at least one FES beam splitter and substantially collimates the light signal and focuses the substantially collimated light signal into a first FES optical fiber having a core diameter of about 1-20 micrometers;
• and
• a second FES channel, including at least one second FES lens that receives the light signal from a second output of the FES beam splitter and substantially collimates the light signal and focuses the substantially collimated light signal into a second FES optical fiber having a core diameter of about 1-20 micrometers;
• and
• wherein the at least one first FES lens and the first FES optical fiber are configured, spaced, and arranged to decrease the field of view (FOV) on an object plane of the three-dimensional optical information storage medium and increase the areal storage density of the three-dimensional optical information storage medium;
• and
• wherein the at least one second FES lens and the second FES optical fiber are configured, spaced, and arranged to decrease the FOV on the object plane of the three-dimensional optical information storage medium and increase the areal storage density of the three-dimensional optical information storage medium;
• and
• wherein at least one of (a) the at least one FES beam splitter, (b) the at least one first FES lens, (c) the at least one second FES lens, and (d) at least one other optical element are configured, spaced, and arranged so that the first and second FES channels have their object plane foci displaced in the axial direction so that the light signals carried by the first and second FES optical fibers can be detected and processed to generate the FES signal.

An optical system for generating a focus error signal (FES) and a data signal from a moving three-dimensional optical information storage medium, comprising:

• an FES subsystem comprising optical elements, wherein:
• the optical elements comprise first and second optical fibers used for differential confocal FES detection from the three-dimensional optical information storage medium, the first and second optical fibers having different foci with respect to the optical information storage medium and core diameters of about 1-20 micrometers;
• and
• wherein the optical elements are configured, spaced, and arranged to decrease a field of view (FOV) on an object plane of the three-dimensional optical information storage medium, and substantially eliminate intersymbol crosstalk from reading the three-dimensional optical information storage medium;
• and
• a data subsystem comprising a third optical fiber focused with respect to the three-dimensional optical information storage medium between the foci of the first and second optical fibers for read signal acquisition from the three-dimensional optical information storage medium, wherein one or more of the optical elements of the FES subsystem are configured and positioned to cooperate with the respective first and second optical fiber to provide an A value of 0-10, according to the following equation:
• A
• =
• 2
• ⁢
• π
• ⁢
• a
• 0
• ⁢
• r
• 0
• λ
• ⁢
• d
• =
• 2
• ⁢
• π
• ⁢
• r
• 0
• 1.22
• D
• A
• (
• Equation
• ⁢
• 1
• )
• where:
• a0=the pupil of the one or more of the optical elements of the FES subsystem, d=the distance of the one or more of the optical elements of the FES subsystem from the respective optical fiber, r0=the respective first and second optical fiber core radius and λ the wavelength of light in the one or more optical elements, a0/d defines a numerical aperture (NA) of the one or more of the optical elements of the FES subsystem, and DA in Equation 1 is the Airy disk diameter given by 1.22λ d/a0=1.22λ/NA.