Browse Prior Art Database

Write Verify System for Field Modulation Optical Recording

IP.com Disclosure Number: IPCOM000103505D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 48K

Publishing Venue

IBM

Related People

Belser, KA: AUTHOR

Abstract

A typical magneto-optical (MO) optical disk recording system consists of a laser 1, a collimation lens 2, a beam splitter 4, an objective lens 5, a disk 6, a bias field magnet 11, a transfer lens 7, and a signal detector 10. Normally, only the central beam is present and recording is done by pulsing the laser power. (Image Omitted)

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Write Verify System for Field Modulation Optical Recording

      A typical magneto-optical (MO) optical disk recording system
consists of a laser 1, a collimation lens 2, a beam splitter 4, an
objective lens 5, a disk 6, a bias field magnet 11, a transfer lens
7, and a signal detector 10.  Normally, only the central beam is
present and recording is done by pulsing the laser power.

                            (Image Omitted)

      In an alternate scheme to be considered here the recording can
be done by modulation of the bias field generated by the bias magnet
11.  In this later case the laser power is not modulated to record
data.  The beam power is controlled to be high during writing and low
during reading.

      A diffraction grating 3 can be inserted into the optical path
to create three beams.  The central beam has 90% of the light power
and the first order diffraction beams have 5% of the power each.  The
central beam is used in optical recording because it has enough power
to heat the disk.

      The first order beams are oriented so that they are aligned
along the track being recorded.  One beam leads the recorded
information and one beam trails.  The stop 8 is used to eliminate the
light energy in the leading beam.  The training and write beams are
separated by mirrors 9 and directed toward separate detection
electronics.

      There is enough energy in the trailing beam to read the
previously recorded data...