Browse Prior Art Database

SEMICONDUCTOR INJECTION LASERS WITH QUANTUM SIZE EFFECT TRANSPARENT WAVEGUIDING

IP.com Disclosure Number: IPCOM000025577D
Original Publication Date: 1986-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 143K

Publishing Venue

Xerox Disclosure Journal

Abstract

It is of great interest to have semiconductor lasers that possess transparent waveguides between the active region of the laser and its end mirror facets. Examples of such structures are disclosed in U.S. Patent Application Serial No. 524,623, filed August 19, 1983. Proposed here is to make the active region even thinner at regions adjacent to the mirror facets thereby making it possible to pump the laser along its entire cavity length while providing an emitting aperture for the laser that is quite large, resulting in low beam divergence in the plane perpendicular to its p-n junction. This is accomplished by using the masking techniques taught in U.S. Patent 4,448,797 to provide the structural growth, for example, shown in Figure 1, The mask geometry dimensions must be capable of providing growth rate ratios in the central region of the mask compared to outer regions of the mask underneath the rnask lip as high as 200:1.

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Page 1 of 4

XEROX DISCLOSURE JOURNAL

SEMICONDUCTOR INJECTION LASERS Proposed Classification WITH QUANTUM SIZE EFFECT TRANS-
PARENT WAVEGUIDING
Robert D. Burnham
Donald R. Scifres

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

21 rx 20 -

-

2s

I

-

14

12

, ZZYl. x

FIG. I L X L Y

-

168

98 / 23- 1

2

FIG. 3

Volume I1 Number 2 March/Aprll 1986 97

)4-- ~32 344 I

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Page 2 of 4

SEMICONDUCTOR INJECTION LASERS WITH QUANTUM SIZE EFFECT TRANSPARENT WAVEGUIDING (Cont'd)

41 50

FIG. 5

  XEROX DISCLOSURE JOURNAL Volume 11 Number 2 March/April 1986

98

[This page contains 1 picture or other non-text object]

Page 3 of 4

SEMICONDUCTOR INJECTION LASERS WITH QUANTUM SEE EFFECT TRANSPARENT WAVEGUIDING {Cont'd)

It is of great interest to have semiconductor lasers that possess transparent waveguides between the active region of the laser and its end mirror facets. Examples of such structures are disclosed in U.S. Patent Application Serial No. 524,623, filed August 19, 1983. Proposed here is to make the active region even thinner at regions adjacent to the mirror facets thereby making it possible to pump the laser along its entire cavity length while providing an emitting aperture for the laser that is quite large, resulting in low beam divergence in the plane perpendicular to its p-n junction. This is accomplished by using the masking techniques taught in U.S. Patent 4,448,797 to provide the structural growth, for example, shown in Figure 1, The mask geometry dimensions must be capable of providing growth rate ratios in the central region of the mask compared to outer regions of the mask underneath the rnask lip as high as 200:1.

Semiconductor laser 10 in Figure 1 comprises substrate 12 of n-GaAs upon which are epitaxially deposited cladding layer of n-Ga I-~A~~AS, active region 16 comprising n-p or undoped Gal-xA1xAs, cladding layer 18 of ~-GEL~-~AI~AS and cap layer 20 of pf-GaAs.

Figures 2 and 3 illustrate the bandgap profile for a different semiconductor laser 31 than that shown in Figure i. Laser 31 differs by having inner cladding layers 34 and 36 as well as outer cladding layers 38 and 40. Active region 16 comprises a single quantum well 30 of p, n or undoped Gal-xAl,As or GaAs. Figure 2 is the lateral bandgap profile at line x-x in Figure 1 whereas Figure 3 is the lateral bandgap profile at line y-y in Figure 1, which is at the very thin end portions 160 near the laser facets 22 and 23. To be noted is that the optical mode profile 32 of the propagating opticat wave significantly spreads out In end portions 16B due to the thinness of active region 16 at this region, creat...