Browse Prior Art Database

LASER MIRROR FACET COATINGS

IP.com Disclosure Number: IPCOM000024877D
Original Publication Date: 1982-Aug-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 76K

Publishing Venue

Xerox Disclosure Journal

Abstract

It is well known that injection laser degradation at the mirror facet is decreased by application of a coating to the laser mirror facets. For example, facet coatings, such as, A120g SiOt, or Si3N.4 are commonly used. These coatings must be insulative in or er no to electrically short out the laser junction. However, owing to lattice mismatch and resulting surface states, significant recombination at the interface still results so that there is an improvement in the catastrophic mirror damage limit of only a factor of two when using these particular coatings. Recently, it has been shown that a factor of 10 improvement can be achieved by use of a zinc diffusion at the facet to eliminate surface recombination.

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LEROX DIXLOSURE JOURNAL

LASER MIRROR FACET COATINGS Donald R. Scifres
Robert D. Burnham
R. Don Yinging Wolf gang Stutius

Proposed Classification
U.S. Cl. 331/94.5H Int. C1. HOls 3/00

It is well known that injection laser degradation at the mirror facet is decreased by application of a coating to the laser mirror facets. For example, facet coatings, such as, A120g SiOt, or Si3N.4 are commonly used. These coatings must be insulative in or er no to electrically short out the laser junction. However, owing to lattice mismatch and resulting surface states, significant recombination at the interface still results so that there is an improvement in the catastrophic mirror damage limit of only a factor of two when using these particular coatings. Recently, it has been shown that a factor of 10 improvement can be achieved by use of a zinc diffusion at the facet to eliminate surface recombination.

We suggest a modified approach wherein AlAs or GaAlAs of high A1 content, or GaAlAs graded to form AlAs at the facet/coating interface, be coated onto the laser facets. Such a coating may be applied with MBE, CVD, MO-CVD, low pressure MO-CVD or plasma-assisted low pressureoMO-CVD. These films can be depositied at low enough temperatures, e.g., 410 C to be attractive for facet coatings since such temperatures will not cause crystal damage to the injection laser. After deposition, this film can be oxidized in a dry oxygen atmosphere to provide an insulating layer with very low inte...