Designing a High Speed 1310nm AlGaInAs/AlGaInAs VCSEL using MgO/Si Top DBR and GaInAsP/InP Bottom DBR

Abstract

In this paper, a 1310nm intracavity structure Vertical Cavity Surface Emitting Laser (VCSEL) has been designed using quaternary compound material of AlGaInAs in both QW and barrier but with different composition. This choice has been made instead of choosing widely used GaInAsP/ InP, GaInAsN/ GaAs to gain some advantages. This combination has shown good band offset in the conduction band. Lattice matching has been obtained in the layers from the substrate up to the top contact layer except the quantum well (QW) layers where small amount of compressive strain of 1.55% has been used. From the substrate up to the top contact layer, fabrication can be done by epitaxial growth without any difficulty. Reduction in height by using 5 pairs of the top dielectric DBR mirror system of MgO/ a-Si is an attraction of this design which can be fabricated by evaporation technique. Dissipation in the bottom DBR due to current flow has been eliminated by using intracavity structure which also gave a way out for the current flow bypassing the dielectric top DBR. The active material compositions have been chosen to obtain a peak gain at 1310nm. The end result of this design is a top emitting VCSEL based on InP substrate using a different structure which is capable of producing 1310nm light output and which can be constructed easily using widely used epitaxial techniques mixed with the evaporation technique for the top DBR mirror system. The structure is suitable for use in optical ICs.