Browse Prior Art Database

Polar Diode Laser

IP.com Disclosure Number: IPCOM000115899D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Voegeli, O: AUTHOR

Abstract

Lasers using a resonating cavity of cylindrical or annular shape have been proposed previously (1). As some minimal cavity diameter is required to support lasting action, the associated excitation power is very large; also, the circular cavity shape permits many radial and tangential resonating modes to coexist. Such prior-art cylindrical lasers need hence be constructed from discrete components and can be used only to deliver high levels of pulsed output power having a broad modal and frequency spectrum.

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Polar Diode Laser

      Lasers using a resonating cavity of cylindrical or annular
shape have been proposed previously (1).  As some minimal cavity
diameter is required to support lasting action, the associated
excitation power is very large; also, the circular cavity shape
permits many radial and tangential resonating modes to coexist.  Such
prior-art cylindrical lasers need hence be constructed from discrete
components and can be used only to deliver high levels of pulsed
output power having a broad modal and frequency spectrum.

      This invention describes a laser having a polar symmetry that
delivers a single radial-mode CW output at power levels that allow it
to be built as a solid state diode laser.  This is made possible by
employing a novel cavity whose more complex mirror geometry may be
readily fabricated by photolithographic etching using (2).  The
modified cavity comprises, as shown in the Figure, a collection of
radial spokes that merge into a concentric annular hub.  A choice of
suitable length and width of the spokes restricts mode oscillation to
the radial directions at a low value of threshold current.
Phase-locking of the many radial beams is achieved within the common
hub region.  Here the radial beams overlap progressively toward the
inner hub-mirror while a fraction of the reflected beam enters the
adjacent spoke.  The degree of such coupling between spokes can be
increased by flaring the inner end of the spoke toward the hub
region. ...