摘要:
There is provided an optical multiplexer including: a substrate having a plurality of beam transmitting portions; and diffraction gratings diffracting beams irradiated to the beam transmitting portions at different angles, each diffraction grating being formed in the corresponding beam transmitting portion. Accordingly, it is possible to reduce an alignment error and manufacturing cost and to reduce the entire size of a recording apparatus or a reproducing apparatus.
摘要:
Provided are optical information processing apparatus and method. In the optical information processing apparatus and method, when the recording regions in which optical information is recorded in an angular multiplexing scheme overlap with each other, a recording angle and a recording position for optical information is adjusted so as to improve reproducing efficiency of readout beams reproduced from the overlap recording regions, so that heights of “null” for diffraction energy reproduced from the recording regions and overlap recording regions can be lowered. Accordingly, it is possible to reduce crosstalk noise during the recording and producing of the optical information and to improve optical information recording quality and reproducing efficiency
摘要:
There is provided an optical multiplexer including: a substrate having a plurality of beam transmitting portions; and diffraction gratings diffracting beams irradiated to the beam transmitting portions at different angles, each diffraction grating being formed in the corresponding beam transmitting portion. Accordingly, it is possible to reduce an alignment error and manufacturing cost and to reduce the entire size of a recording apparatus or a reproducing apparatus.
摘要:
A holographic storage system includes a beam supplying unit for supplying an incident beam including data read from a plurality of tracks on a holographic medium; a transferring unit for receiving the incident beam and producing a focused beam; a tracking servo unit for receiving a first portion of the focused beam through a plurality of pinholes and reflecting a second portion of the focused beam back to the transferring unit through a reflecting section simultaneously, wherein the tracking servo unit moves the transferring unit or the pinholes to adjust the amount of the first portion of the focused beam to thereby retrieve data from a target track, and wherein the second portion of the focused beam reflected back to the transferring unit is converted into a return beam by the transferring unit; and a focusing servo unit for compensating for vertical movements of the holographic medium.
摘要:
In order to pick up a digital storage medium including a holographic storage medium and a reflective storage medium, a first and a second beam each of which has a different wavelength are used and a reflected beam and a reconstructed signal beam are propagated through a propagation path, wherein the first beam is reflected by the digital storage medium to generate the reflected beam and the second beam is diffracted by a holographic interference pattern in the holographic storage medium to generate the reconstructed signal beam. A polarizing beam splitter is used to split the reflected beam from the propagation path while a laser line mirror is used to separate the reconstructed signal beam from the propagation path.
摘要:
In a storing mode of an apparatus for storing and retrieving a sequence of digital page data, a first/second complex reference beam and a modulated signal beam converge on a storing location to generate a sequence of first/second interference patterns to be sequentially stored on a holographic medium. A shift selectivity of the first complex reference beam is larger than that of the second complex reference beam so that the second interference pattern is used as a servo pattern to sequentially determine where the first interference patterns have been stored.
摘要:
A method for mapping 2N message N-tuples into 2N+1 codeword (N+1)-tuples is developed. The 2N+1 codeword (N+1)-tuples are categorized into M subsets of codeword (N+1)-tuples, wherein M is an integer larger than 1, each subset G has NG codeword (N+1)-tuples and the total number of codeword (N+1)-tuples in the M subsets is 2N. Each subset G has a predetermined number KG of lower bits and a predetermined number (N+1−KG) of higher bits, and the number of lower bits in every codeword (N+1)-tuple in any subset is not equivalent to that of lower bits in every codeword (N+1)-tuple in any other subset. The 2N message N-tuples are matched with the 2N codeword (N+1)-tuples in the M subsets, respectively, in one-to-one correspondence to generate a lookup table.
摘要:
An optical information processing apparatus includes: a light source; a reference beam guiding optical system guiding a reproducing reference beam emitted from the light source to an optical information storage medium in which optical information is recorded at multiplexing angles; a signal beam guiding optical system guiding a reproduced signal beam, which is reproduced from the optical information storage medium in the coaxial line with the reproducing reference beam and in the opposite direction of the traveling direction of the reproducing reference beam and is a phase-conjugation wave of a recording signal beam used at the time of recording the optical information; and an optical information detector detecting the reproduced signal beam guided by the signal beam guiding optical system. Accordingly, it is possible to reduce the manufacturing cost, to enhance the multiplexing density of optical information, and to simplify and miniaturize the entire optical information processing apparatus.
摘要:
An angular multiplexing apparatus for a holographic storage medium. The angular multiplexing apparatus includes a reconstructing reference beam generator, translated in parallel to a number of positions, for generating a number of reconstructing reference beams which propagate in parallel to one another at the positions, respectively, and a mirror array having a plurality of planes of reflection for generating a plurality of reflected beams which are converged into a reconstructing position of the holographic storage medium.
摘要:
A holographic ROM reader having a servo control is disclosed. The holographic ROM reader includes an objective lens for focusing light reflected from a storage medium, a pinhole plate provided with a pinhole, a diffraction grating, embedded into the pinhole of the pinhole plate, for diffracting the light focused by the objective lens to produce 0th order diffracted light, +1st order diffracted light and −1st order diffracted light therethrough, a photo detector for detecting the amounts of the 0th order, the +1st order and the −1st order diffracted light, and a servo controller for comparing an amount of light of an overlapped area of the 0th order diffracted light and the +1st order diffracted light with an amount of light of an overlapped area of the 0th order diffracted light and the −1st order diffracted light to control the position of the objective lens to pass the light through a center of the diffraction grating if the amounts of light are not identical to each other.