Browse Prior Art Database

Self Aligned Spatial and Wavelength Tunable Masterwriter System

IP.com Disclosure Number: IPCOM000121364D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Yung, BH: AUTHOR

Abstract

To make an optical media, a masterwriting system is needed to write the servo information on the resist-coated quartz substrate. Stamper is then generated by subsequent electroforming and peel-off process. To optimize the use of resist technology, a tunable laser-based system is desirable. The use of tunable laser will affect the acousto-optical (AO) modulator (AOM) alignment. Also, to adjust servo pitch spacing, i.e., spatial tuning, the beam combining beam splitter angle needs to be adjusted. This would upset the alignment of the groove writing beam.

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Self Aligned Spatial and Wavelength Tunable Masterwriter System

      To make an optical media, a masterwriting system is
needed to write the servo information on the resist-coated quartz
substrate.  Stamper is then generated by subsequent electroforming
and peel-off process. To optimize the use of resist technology, a
tunable laser-based system is desirable.  The use of tunable laser
will affect the acousto-optical (AO) modulator (AOM) alignment.
Also, to adjust servo pitch spacing, i.e., spatial tuning, the beam
combining beam splitter angle needs to be adjusted.  This would upset
the alignment of the groove writing beam.

      Two improvements over existing masterwriting system is
described.  These will help minimize the alignment efforts.

      For spatial tuning compensation, an alignment cube of the same
dimension and refractive index as the beam combiner cube is inserted,
as shown in Fig. 1.  As the beam combiner is turned to change the
pitch spacing, the alignment cube orientation is also turned of equal
angle but in opposite direction (Fig. 2).  This will cancel the
refractive effect due to the beam combiner.

      Wavelength or spectral compensation for the AO modulator
alignment due to laser wavelength shift can be accomplished by
inserting the AO modulator in a conjugating lens pair (Fig. 3), and
the assembly is translated to maintain proper Bragg's angle.  The
amount of translation is calculated and servoed from a spectrometer
output. ...