CN-122024776-A - Holographic storage

Abstract

A holographic data storage system includes an emitter system, a holographic recording medium, and an input waveguide network formed from one or more multimode optical waveguides. The holographic recording medium has a plurality of recording areas, each recording area being optically coupled to a corresponding outcoupling area of the plurality of outcoupling areas of the input waveguide network, the holographic data storage system being arranged to permanently write data of the input light beam received at any one of the outcoupling areas to the corresponding recording area. The controller is coupled to at least one of the emitter system and at least one controllable guiding element of the input waveguide network and controls at least one optical property of the input light beam or the at least one guiding element so as to guide the input light beam from the in-coupling region to any selected out-coupling region of the plurality of out-coupling regions. A similar waveguide network is provided to carry the reference beam and the output beam.

Inventors

• D.J. KELLY
• B. C. Thomson
• D narayanan
• A. I.T. Luo Siqiang
• A. Georgio

Assignees

• 微软技术许可有限责任公司

Dates

Publication Date

20260512

Application Date

20210222

Priority Date

20200326

Claims (20)

1. 1. An optical system, comprising: A first optical system component; a plurality of second optical system components; multimode optical waveguide network, and A controller configured to: Selecting a second optical system component of the plurality of second optical system components, and By controlling the phase characteristics or angles at which the light beam is coupled into the multimode optical waveguide network, the light beam is directed from or to the first optical system component or to or from the selected second optical system component for causing a plurality of modes to be stored in a single recording area.
2. 2. The optical system of claim 1, wherein causing the optical beam to be directed from or to the first optical system component or to or from the selected second optical system component comprises configuring a directing element to cause the optical beam to be directed from an in-coupling region of the multimode optical waveguide network to a selected any one of a plurality of out-coupling regions of the multimode optical waveguide network.
3. 3. The optical system of claim 1, wherein causing the light beam to be directed from or to the first optical system component or to or from the selected second optical system component further comprises configuring a directing element of the multimode optical waveguide network.
4. 4. The optical system of claim 3, wherein configuring the guiding element comprises changing the guiding element from a transmissive state to a reflective state.
5. 5. The optical system of claim 1, wherein the first optical system component comprises the guide element and the selected second optical system component comprises a second guide element.
6. 6. The optical system of claim 3, wherein the guiding element alters an optical characteristic of the first optical system component.
7. 7. The optical system of claim 1, wherein the first optical system component comprises a first plurality of guide elements and the selected second optical system component comprises a second plurality of guide elements.
8. 8. An optical system according to claim 1, wherein the multimode optical waveguide network is arranged to direct a light beam from or to the first optical system component and to or from any selected second optical system component of the plurality of second optical system components.
9. 9. An apparatus, comprising: Processor, and A memory comprising computer-executable instructions that, when executed by the processor, cause the processor to: Selecting a first optical system component of a plurality of optical system components, and By controlling the phase characteristics or angle at which the light beam is coupled into the multimode optical waveguide network, the light beam is directed from or to the second optical system component or to or from the selected first optical system component for enabling multiple modes to be stored in a single recording area.
10. 10. The apparatus of claim 9, wherein the second optical system component comprises an emitter system configured to emit the light beam in the form of a multimode optical signal encoding a plurality of image pixels into a plurality of propagation modes of the light beam propagating in different directions.
11. 11. The apparatus of claim 9, wherein the plurality of patterns to be stored in the single recording area are created with different phase characteristics, different angles, or both of the light beams.
12. 12. The apparatus of claim 9, wherein causing the light beam to be directed from or to the second optical system component or to or from the selected first optical system component comprises configuring a guiding element of the multimode optical waveguide network.
13. 13. The apparatus of claim 12, wherein configuring the directing element comprises configuring the directing element to cause the optical beam to be directed from an in-coupling region of the multimode optical waveguide network to a selected one of a plurality of out-coupling regions of the multimode optical waveguide network.
14. 14. The apparatus of claim 12, wherein configuring the guiding element comprises changing the guiding element from a reflective state to a transmissive state or from the transmissive state to the reflective state.
15. 15. The apparatus of claim 9, wherein the second optical system component comprises a guide element, and wherein the guide element alters an optical characteristic of the first optical system component.
16. 16. An optical system, comprising: A first optical system component comprising a guiding element; A second optical system component; multimode optical waveguide network, and A controller configured to cause the light beam to be directed from the first optical system component to the second optical system component by controlling a phase characteristic or angle at which the light beam is coupled into the multimode optical waveguide network for causing a plurality of modes to be stored in a single recording area.
17. 17. The optical system of claim 16, further comprising an emitter system configured to emit the light beam in the form of a multimode optical signal.
18. 18. The optical system of claim 17, wherein the multimode optical signal encodes a plurality of image pixels into a plurality of propagation modes of the light beam propagating in different directions.
19. 19. The optical system of claim 16, wherein the multimode optical waveguide network is arranged to direct an optical beam to the second optical system component.
20. 20. The optical system of claim 16, wherein causing the optical beam to be directed from or to the first optical system component or to or from the selected second optical system component comprises configuring a directing element to cause the optical beam to be directed from an in-coupling region of the multimode optical waveguide network to a selected any one of a plurality of out-coupling regions of the multimode optical waveguide network.

Description

Holographic storage The application is a divisional application of patent application with the application number 202180024730.3, the patent application name of holographic storage, which is filed on 22 days of 2021, 02. Technical Field The present disclosure relates generally to holographic storage. Background Holographic storage is a form of computer storage in which information is recorded in a photosensitive holographic recording medium by exposing the medium to an optical pattern. For example, a region (sub-volume) of the medium may be exposed to an optical interference pattern caused by interference between the reference beam and the input beam embedded in the dataset. For example, the beam may be a laser beam generated using a single laser and beam splitter. Spatial Light Modulation (SLM) may be used to embed a data set in an input beam, for example an image encoding the data set may be spatially modulated into the input beam. For the avoidance of doubt, the terms "light," "optical," and the like herein are not limited to visible light. Holographic storage may be achieved, for example, using infrared or ultraviolet light beams within the invisible portion of the electromagnetic spectrum. With sufficient beam power and exposure time, the optical interference pattern causes a persistent state change within the sub-volume (at which point the interference pattern is referred to herein as a persistent record or write sub-volume). The change state of the sub-volume is such that when the sub-volume is later exposed to a substantially matching reference beam, the interaction between the matching reference beam and the sub-volume produces an output beam that substantially matches the original input beam in the sense that the data set originally embedded in the input beam can be recovered from the output beam (this may be referred to herein as reading the recorded pattern). Instead of storing a single bit as discrete cells, a single interference pattern may encode a large number (e.g., millions) of bits. For example, the dataset may be a mega pixel image embedded in the input beam. Furthermore, by exploiting the sensitivity of a particular form of holographic recording medium to small variations in the reference beam angle, many such patterns (e.g. hundreds or thousands) can be recorded into the same sub-volume. For such a medium, when the reference beam is used to create an interference pattern at a given angle, the recorded pattern can only be read using a reference beam that is very matched to the reference beam originally used to create it. This effect can be exploited to record multiple patterns (encoding different data sets) to the same sub-volume at different reference beam angles. Theoretically, the data storage capacity is limited only by the wavelength of the light beam, which may reach hundreds of megabytes per cubic millimeter, and ultraviolet light may reach tens of gigabytes. In practice, other limiting factors may exist, but high density data storage has great potential. Disclosure of Invention This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The claimed subject matter is also not limited to implementations that solve any or all disadvantages noted herein. Providing spatially multiplexed holographic data storage/retrieval systems on holographic recording media, in the sense that different physical sub-volumes of the media can be written/read, typically requires some form of mechanical actuator(s) to effect mechanical movement of the controllable holographic media to move the media relative to, for example, a read/write head of the system (from which an input beam and a reference beam are emitted and at which an output beam is detected) or relative to the media. This in turn limits the speed of data writing/reading, as well as the scalability and reliability of such systems. Aspects of the technology disclosed herein reduce or eliminate the need for such mechanical movement. A first aspect herein provides a holographic data storage system comprising an emitter system, at least one holographic recording medium, and an input waveguide network formed of one or more multimode optical waveguides for carrying a plurality of propagation modes simultaneously. The transmitter system is configured to transmit an input light beam in the form of a multimode optical signal encoding a plurality of image pixels into a plurality of propagation modes of the input light beam propagating in different directions. The input waveguide network has a plurality of outcoupling regions and an incoupling region for receiving an input beam from the transmitter system. At least one holographic recording medium has a plurality of recording areas, ea