Read/write system for optical disc apparatus with fiber optics
AssigneeAT&T Bell Laboratories
InventorEugene I. Gordon
Life of this patent
Estimating the term…
Abstract
A read/write system is disclosed for optical disc apparatus. The light source is removed from the head and optically coupled to the disc by a single-mode fiber which acts as a spatial filter. Adverse effects on the light source due to reflection from the disc are avoided by making the fiber length greater than one-half the coherence length of the source. A sparing switch and combiner component may be included in the system. An array of discrete light sources, each coupled to an associated fiber, may also be employed for multiple track accessing.
Claims15
Optical disc apparatus including means for accessing information in a recording medium comprising:
- a laser source positioned at an area remote from the recording medium;
- and
- a single-mode optical fiber adapted to transmit light from the laser at an input end to an area above the surface of the recording medium and to produce at its output end a spot having the lowest order Gaussian mode distribution.
Optical disc apparatus including means for accessing information in a recording medium comprising:
- at least two laser sources positioned at an area remote from the medium, the light from said sources being polarized;
- a plurality of single-mode fibers which maintains the polarization of light transmitted therethrough, with at least a first and second fiber receiving the light output from a respective laser source and at least a third fiber transmitting the light to an area above the recording medium so that a light spot at its output has the lowest order Gaussian mode distribution;
- and
- an optical component adapted to receive light from both the first and second fibers coupled to the sources and to transmit light from at least one source to the third fiber.
Optical disc apparatus including means for accessing information simultaneously in several tracks in a recording medium comprising:
- a plurality of light sources positioned at an area remote from the medium, the light from said sources being polarized;
- and
- a plurality of single-mode fibers which maintains the polarization of light transmitted therethrough, each fiber adapted to receive light at an input end from one of the sources and transmit the light to an area above the recording medium at an output end, the output end of each fiber being positioned in a groove formed within a block so that the fibers are positioned in an array over the area of the recording medium and light from each fiber will be incident on a different one of the several tracks.
Dependencies are inferred from the claim text.