Browse Prior Art Database

IMPROVEMENTS IN REAL REFRACTIVE INDEX GUIDE LASERS

IP.com Disclosure Number: IPCOM000025532D
Original Publication Date: 1985-Dec-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 129K

Publishing Venue

Xerox Disclosure Journal

Abstract

Semiconductor lasers can generally be divided into two generic classes: (1) real refractive index guided lasers, including, for example, the channeled substrate planar (CSP) laser and the mesa substrate laser and (2) gain guided lasers, including, for example, conventional contact stripe planar lasers and V-groove I asers.

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CEROX DISCLOSURE JOURNAL

INTERNAL WAVEGUIDE STRUCTURE

12 \

IMPROVEMENTS IN REAL REFRACTIVE INDEX GUIDE LASERS US. Cl. 372/45
William Streifer

Proposed Classification

Int. C1. HOls 3/19

Donald R. Scifres Robert D. Burnham

/FACET 14

REAL REFRACTIVE

/LASER 10

CONTACT STRIPE 18

\FACET 16

/FACET 24

   INTERNAL WAVEGUIDE -STRUCTURE 22

-REAL REFRACTIVE INDEX 'GUIDED

SEMICONDUCTOR

LASER 20

Volume 10 Number 6 Novernber/December 1985 375

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II

I I I 1

-1 I 1 I1

II ,

FIG. 7

CONTACT STRIPE 28

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

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IMPROVEMENTS IN REAL REFRACTIVE INDEX GUIDE LASERS (Cont'd)

Semiconductor lasers can generally be divided into two generic classes: (1) real refractive index guided lasers, including, for example, the channeled substrate planar (CSP) laser and the mesa substrate laser and (2) gain guided lasers, including, for example, conventional contact stripe planar lasers and V-groove I asers.

Gain guided lasers in many cases have higher threshold currents than do real refractive index guided lasers. They operate simultaneously in many longitudinal modes, possess an output beam that is astigmatic and their modal pattern may change with variation in pumping current and with aging. It would appear, then, that real refractive index guided lasers have many advantages over gain guided lasers. However, several of the characteristics of this laser can create difficulties.

The single longitudinal mode output of the real refractive index guided laser is theoretically desirable, but if the lasing mode jumps during laser pumping from one wavelength to another, the wavelength change can become a significant source of noise. This source of noise is absent in the multimode gain guided laser. A second difficulty in using real refractive index guided lasers occurs when some, although small, amounts of optical power are reflected internally at the laser facet back into the laser cavity. This causes changes in light intensity and in lasing wavelength and may, therefore, prevent the laser from successfully operating in some applications, such as optical recording.

The proposal here seeks to retain guided laser while at the same difficulties.

the advantages of the real refractive index time eliminating the two above-mentioned

Figure 1 illustrates the top or p an view of a real refractive index guided semiconductor laser 10 which has an internal real index waveguide structure 12, which may be formed during epitaxial growth over a channel or mesa feature formed on a substrate surface. Waveguide structure 12 is perpendicular to parallel end facets 14 and 16. Laser 10 has formed in its surface...