Multi-channel optical head and data storage system
AssigneeInternational Business Machines Corporation
InventorsJames M. Zavislan, Bulent N. Kurdi
Life of this patent
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Abstract
A multichannel optical head and data storage system employs an integrated-optical read channel. The read channel may be fabricated on a planar waveguide structure that separates the data signals of the multiple lasers. The read channel includes focus error sensors and track error sensors. The optical head may be used for amplitude recording systems such as phase-change erasable and write-once media, ablation media, dye-polymer media, and OD-ROM systems.
Claims19
A multi-channel laser optical system for reading information on an optical storage medium having machine readable information encoded thereon, the optical system being adapted to transmit a plurality of focused laser output beams to the optical storage medium so that the optical storage medium receives the focused laser output beams at a selected focal distance, and reflects a plurality of information modulated signal beams for processing, the optical system comprising:
- a multiple channel laser optical source for generating a plurality of spatially separated laser output beams;
- an objective lens positioned to receive said laser output beams and to focus said laser output beams at the selected focal distance from said objective lens, said objective lens also being positioned to receive a plurality of information modulated signal beams reflected by an optical storage medium positioned at said focal distance, and to transmit said information modulated signal beams toward said laser optical source;
- a multi-mode optical waveguide structure positioned to receive said information modulated signal beams and to produce a plurality of redirected, spatially separated signal beams;
- means for orienting and coupling said information modulated signal beams into said optical waveguide structure in a plurality of different modes;
- and
- a plurality of optical detectors positioned to receive said spatially separated signal beams from said optical waveguide structure and to produce a plurality of output signals representing information contained on said optical data storage medium.
A method for reading data from an optical storage medium rotating about a central axis and having information-containing data channels on a surface thereof, said method comprising the steps of:
- activating a multiple laser optical source to generate a plurality of spatially separated laser output beams;
- producing a plurality of reflected signal beams by directing said plurality of spatially separated laser output beams to the optical storage medium such that each laser beam strikes a respective data channel on the storage medium;
- directing said reflected signal beams to a multi-mode optical waveguide positioned to receive said reflected signal beams to produce a plurality of redirected, spatially separated and modally discrete signal beams;
- and
- directing said spatially separated signal beams to a plurality of optical detectors positioned to receive said spatially separated signal beams and to produce a plurality of output signals representing the information contained on said optical data storage medium.
An optical system, comprising:
- an optical storage medium having multiple data channels containing machine readable information defined on the surface thereof;
- means for rotating said optical storage medium about a central axis;
- beam source means for generating and directing a plurality of incident light beams to said optical storage medium, so that said incident light beams respectively strike said multiple data channels;
- beam redirecting means for (1) receiving said incident beams in a first direction and allowing them to pass transversely therethrough, (2) receiving light reflected from said data storage medium representing reflected signal beams in a second direction substantially opposite to said first direction, and (3) redirecting said reflected signal beams by modal separation into a plurality of spatially separated output beams in a third direction;
- optical detector means for receiving said separated output beams and for providing a plurality of output signals corresponding to said output beams;
- and
- circuit means for processing said output signals into a plurality of machine readable data signals.
Dependencies are inferred from the claim text.