Browse Prior Art Database

Packaging of Compact Laser Arrays

IP.com Disclosure Number: IPCOM000103240D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 51K

Publishing Venue

IBM

Related People

Dube, RR: AUTHOR [+2]

Abstract

Closely spaced laser arrays are important to various applications, such as printing and optical communication. Normally such arrays may be accessed using wire bonding. However, for center-to-center spacing of less than 100 microns, wire bonding using gold balls cannot be used because the gold balls are generally larger than 75 microns. Moreover, the proximity of the lasers to the bonding sites gives rise to micro-cracks in the lasers. In order to solve this problem, a second metallization level may be introduced and the contacts are made on that level. This involves several additional masks and, as such, increases process complications. As a consequence, laser array structures with elements spaced closer than 100 microns apart are difficult to produce.

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Packaging of Compact Laser Arrays

      Closely spaced laser arrays are important to various
applications, such as printing and optical communication. Normally
such arrays may be accessed using wire bonding. However, for
center-to-center spacing of less than 100 microns, wire bonding using
gold balls cannot be used because the gold balls are generally larger
than 75 microns. Moreover, the proximity of the lasers to the bonding
sites gives rise to micro-cracks in the lasers.  In order to solve
this problem, a second metallization level may be introduced and the
contacts are made on that level.  This involves several additional
masks and, as such, increases process complications.  As a
consequence, laser array structures with elements spaced closer than
100 microns apart are difficult to produce.

      In EP printheads, for example, requisite high optical
magnification introduces serious optics problems for elements spaced
more than 100 microns apart.  Thus, there is a need for a laser
structure with four elements spaced very close together.

      We propose to arrange the laser array as shown in the figure.
Two embodiments are shown in the figure.  The 45 degree angle mirror
is commercially available.  These mirrors are oriented to reflect the
laser beams out of the plane of the array.  In this arrangement the
laser beams are individually addressable (not phased arrays) with
minimal center-to-center separation.  The large area around the
lasers facilita...