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Three Layer Injection Laser

IP.com Disclosure Number: IPCOM000094855D
Original Publication Date: 1965-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Pilkuhn, MH: AUTHOR [+3]

Abstract

A three-layer semiconductor injection laser is provided in which choice of impurity profile together with control of the width of the active region obtains control of beam losses and beam divergence. Generally, the intensity distribution perpendicular to the junction of an injection laser depends strongly on the boundary conditions imposed by the index of refraction and absorption coefficient of the adjacent layers. Light emitting properties of this injection laser are altered by variation of these parameters.

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Three Layer Injection Laser

A three-layer semiconductor injection laser is provided in which choice of impurity profile together with control of the width of the active region obtains control of beam losses and beam divergence. Generally, the intensity distribution perpendicular to the junction of an injection laser depends strongly on the boundary conditions imposed by the index of refraction and absorption coefficient of the adjacent layers. Light emitting properties of this injection laser are altered by variation of these parameters.

The structure of injection laser 10 confines the radiation to active region 14. This confinement reduces the threshold current density and the internal loss by an order of magnitude relative to the value required when minority carriers are injected into a homogeneous region. The carrier concentration and width of the low P-type doped region can vary over rather wide limits dependent on the output performance desired. A wider active region provides a narrower beam spread perpendicular to the junction plane. To achieve this, the concentration in active layer 14 is reduced to make the minority carrier diffusion length approximately equal to the active region width. This reduces the threshold current to a minimum. For a junction width of three microns, the carrier concentration should be about 3 x 10/17/ cm/-3/ For a low threshold requirement, the concentration in the active region should be from 1018 cm/-3/ to 3 x 10/18/ cm/-3/ and the width should be about one micron.

Two exemplary injection laser structures 10, obtained according to the a...