Multiple beam optical memory system with solid-state lasers

• US 5,483,511 A
• Filed: 02/17/1993
• Issued: 01/09/1996
• Est. Priority Date: 02/17/1993
• Status: Expired due to Fees

• Current Assignee: Optical Communication Products Incorporated (KOCH Industries Incorporated)
• Original Assignee: Vixel Corporation (Broadcom, Inc.)
• Inventors: Jewell, Jack L., Muchnik, Boris J.
• Primary Examiner(s): Epps, Georgia Y.
• Assistant Examiner(s): HINDI, NABIL Z
• Application Number:
  US08/019,141
• Time in Patent Office: 1,056 Days
• Field of Search: 369/44.37, 369/44.23, 369/44.24, 369/109, 369/110, 369/112, 369/124, 369/44.11, 369/13, 369/117, 369/118, 369/119, 369/44.32, 369/103, 369/107, 369/116, 385/33, 250/571
• US Class Current: 369/44.37
• CPC Class Codes: G11B 2007/13727 Compound lenses, i.e. two or more lenses co-operating to perform a function, e.g. compound objective lens including a solid immersion lens, positive and negative lenses either bonded together or with adjustable spacing
• CPC Class Codes: G11B 7/127 Lasers; Multiple laser arrays lasers per se H01S
• CPC Class Codes: G11B 7/1353 Diffractive elements, e.g. holograms or gratings diffraction gratings per se G02B5/18; holograms per se G02B5/32; grating systems G02B27/44
• CPC Class Codes: G11B 7/1378 Separate aberration correction lenses; Cylindrical lenses to generate astigmatism; Beam expanders
• CPC Class Codes: G11B 7/14 specially adapted to record on, or to reproduce from, more than one track simultaneously

Abstract

An optical memory system employing multiple reading/writing optical beams from solid state lasers for simultaneously reading from a writing to multiple tracks of optical media to allow reading/writing of closely spaced adjacent tracks, a number a feature are disclosed. These include using vertical writing surface emitting lasers forming an array of beam sources, using lenslets associated with array, modulating the beams, and providing various optical elements and combinations of optical elements to compensate for beam and system imperfections.

Claims

1. An optical memory system comprising:

an optical recording medium with data arranged substantially linear and parallel tracks;

a plurality of optical sources for generating a plurality of optical beams propagating in substantially the same direction along an optical axis, said plurality of optical beams arranged in an array having at least a first and second dimension, said plurality of optical beams performing substantially identical functions for reading from or writing to said optical recording medium in a parallel fashion;

a plurality of detectors;

an optical means for collecting said optical beams, for focusing said optical beams to form close-spaced spots on said optical recording medium, for collecting said optical beams reflected or transmitted from said optical recording medium, and for directing the reflected or transmitted optical beams onto said plurality of detectors such that each of said detectors receives one of said plurality of beams and emits an electronic signal in response thereto; and

means for processing the signals from said plurality of detectors;

wherein at least some of said optical beams are arranged in first and second subarrays which are substantially linear, said second subarray being offset from said first subarray by a distance equal to approximately one-half the beam separation distance in either array.

2. The optical memory system recited in claim 1, in which said optical recording medium is movable and further comprises means for causing said optical beams to scan said optical recording medium in a direction substantially transverse to said linear direction of said tracks.

3. The optical memory system recited in claim 1, in which at least two of said optical beams are focused onto adjacent tracks.

4. The optical memory system recited in claim 1, in which at least two adjacent beams of said optical beams are focused onto non-adjacent tracks.

5. The optical memory system recited in claim 1, in which said optical system further comprises a plurality of microlenses to modify the convergence or divergence of at least one of said plurality of optical beams.

6. The optical memory system recited in claim 1, in which at least some of said optical beams are arranged in a square array.

7. The optical memory system recited in claim 1, in which at least some of said optical beams are arranged in a rectangular array.

8. The optical memory system recited in claim 1, in which at least some of said optical beams are arranged in an oblique fashion.

9. The optical memory system recited in claim 1, in which the optical recording medium is a disk and the orientation of said first and second subarrays are substantially radial to said disk.

10. The optical memory system recited in claim 1, in which the optical recording medium is a tape and the orientation of said first and second subarrays are substantially along a short dimension of said tape.

11. The optical memory system recited in claim 1, further comprising means for generating, focusing and tracking information, said tracking means including at least one additional beam used exclusively for focusing and not for reading from or writhing to said optical recording medium.

12. The optical memory system recited in claim 1, further comprising means for generating, focusing and tracking information, said tracking means including at least one additional beam used exclusively for tracking and not for reading from or writing to said optical recording medium.

13. The optical memory system recited in claim 1, in which said plurality of optical sources comprises an array of independently addressable solid state lasers.

14. The optical memory system recited in claim 13, in which said optical beam generating means comprises an array of vertical- cavity surface emitting lasers.

15. The optical memory system recited in claim 14, further comprising a moveable focusing lens for focusing said plurality of optical beams onto said optical recording medium, said beam generating means comprising at least four beams for reading data, and said movable focusing lens comprising at most two surfaces which deviate substantially from being flat.

16. The optical memory system recited in claim 1, further comprising actuators for focus control and tracking control of said optical beams.

17. The optical memory system recited in claim 1, in which said plurality of optical beams are focused into said optical recording medium in a substantially planar region which is substantially parallel to said optical recording medium.

18. The optical memory system recited in claim 1, further comprising means for rotating said plurality of optical beams.