Browse Prior Art Database

SEMICONDUCTOR QUANTUM WELL WINDOW LASERS

IP.com Disclosure Number: IPCOM000025534D
Original Publication Date: 1985-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 6 page(s) / 275K

Publishing Venue

Xerox Disclosure Journal

Abstract

This disclosure relates to semiconductor heterostructure lasers having a "window" effect near or adjacent to the facets of the laser. In a patent application Serial No. 462,840 filed February 1, 1983, there is described various embodiments of combination index/gain guided semiconductor lasers. In some of the embodiments, index guiding regions are provided adjacent to the laser .facets. The index guiding attributes are provided through initial selective etching of the laser substrate, prior to growth, to permit the epitaxial growth of very thin layers in these end regions. The very thin deposited active layer at these regions form a thin quantum well region near the mirror facet so that a transparent "window" effect is achieved, allowing long laser life at high optical output powers.

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Page 1 of 6

XEROX DISCLOSURE JOURNAL

SEMICONDUCTOR QUANTUM WELL WINDOW LASERS
Donald R. Scifres
Robert D. Burnham

t2A

Proposed Classification
U.S. C1. 372/45 Int. Cl. HOls 3/19

28

'

FIG. 1

32

FIG. 2

Volume 10 Number 6 November/December 1985 383

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Page 2 of 6

SEMICONDUCTOR QUANTUM WELL WINDOW LASERS (Cont'd)

43

40

-

FIG. 3

-45 48

53

FIG. 5

     XEROX DISCLOSURE JOURNAL Volume 10 Number 6 November/December 1985

/ J2

384

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Page 3 of 6

SEMICONDUCTOR QUANTUM WELL WINDOW LASERS (Cont'd)

This disclosure relates to semiconductor heterostructure lasers having a "window" effect near or adjacent to the facets of the laser.

In a patent application Serial No. 462,840 filed February 1, 1983, there is described various embodiments of combination index/gain guided semiconductor lasers. In some of the embodiments, index guiding regions are provided adjacent to the laser .facets. The index guiding attributes are provided through initial selective etching of the laser substrate, prior to growth, to permit the epitaxial growth of very thin layers in these end regions. The very thin deposited active layer at these regions form a thin quantum well region near the mirror facet so that a transparent "window" effect is achieved, allowing long laser life at high optical output powers.

In applications such as optical disk systems, printer systems, or other such applications requiring focusing of the near field output of the semiconductor laser, it is decidedly advantageous to employ an index guided laser, since these lasers- do not exhibit the astigmatism of gain guided lasers thereby permitting easily accomplished focusing with a simple lens system. However, index guided lasers, normally exhibit single longitudinal mode operation when operated at power levels in excess of several mil liwatts. Single longitudinal mode operation leads to excess noise resulting from the long coherence length of the laser radiation or longitudinal mode "hopping" caused by thermal variation of the laser operation versus time. On the other hand, gain guided lasers will provide multi- longitudinal mode operation, relieving these undesirable effects but requiring a sophisticated lens system to remove the undesirable astigrnatism. This disclosure relates to a laser structure that has multiple longitudinal modes as well as an as t i gm a t i c em i s s i o n char act e r i s t i cs co u p I e d w i t h de s i re d t r a ns pare n t w i n do w characteristics.

According to this disclosure, a semiconductor laser is provided with quantum well window regions in the active region of the laser. The semiconductor laser is provided with one or more layers forming an active region for supporting radiation propagating under laser conditions in an optical cavity established between transverse end facets of the lasers. The laser is characterized by a combination restricting and nonrestricting geometry emu...