Browse Prior Art Database

BURIED SINGLE HETEROSTRUCTURE DFB AND DBR LASERS

IP.com Disclosure Number: IPCOM000023991D
Original Publication Date: 1979-Jun-30
Included in the Prior Art Database: 2004-Apr-01
Document File: 2 page(s) / 326K

Publishing Venue

Xerox Disclosure Journal

Abstract

In Figure 1, a buried single heterostructure laser 10 comprises a GaAs substrate 12 upon which is formed the mesa 14, active layer 16 and a grating 26 on the surface of the active layer 16. This mesa can be made by marking and etching after layer growth. The grating 26 may be fabricated for distributed feedback (DFB Figure 2) or fabricated as a distributed Bragg reflector (DBR Figure 3). Second stage growth provides layers 18, 20 and 22.

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BURIED SINGLE HETEROSTRUCTURE DFB AND DBR LASERS (Cont~d)

In Figure 1, a buried single heterostructure laser 10 comprises a GaAs substrate 12 upon which is formed the mesa 14, active layer 16 and a grating 26 on the surface of the active layer 16. This mesa can be made by marking and etching after layer growth. The grating 26 may be fabricated for distributed feedback (DFB Figure
2) or fabricated as a distributed Bragg reflector (DBR Figure 3). Second stage growth provides layers 18, 20 and 22.

As a DFB laser, optical feedback is provided by placing the grating 26 of Figure 2 at the interface between layers 16 and 20. The grating period must equal an integer multiple of one half the wavelength within the laser optical waveguide. Current flow is restricted to the active layer 16 by the reverse biased p~.njunction 28 and by the higher junction voltage of the p-n junction 30 as compared to the active layer p~njunction 32.

As a DBR laser, the grating 26 of Figure 3 comprises grating portions 26a and 26b. These portions are placed at the interface between layers 16 and 20, The grating portions 26a and 26b placed outside of the laser gain region so that nonradiative recombination losses, which are caused by grating induce...