Design of a LW-VCSEL Optical Source

Abstract

ABSTRACT:There are a number of reasons why light can be used as an efficient carrier of information. As a result, optical communication has gained much importance over the last few decades. The vertical cavity surface emitting laser (VCSEL) is a low cost light source with attractive performance characteristics such as low power consumption, high speed capabilities at low currents, and a circular output beam. These features have madeVCSEL an established component in digital communication networks as the optical source. In this paper, a 1550nm intra-cavity structure Vertical Cavity Surface Emitting Laser (VCSEL) has been designed using quarter nary compound material of AlGaIn Asin both QW and barrier, but with different compositions, and InP as the substrate. Lattice matching has been obtained in the layers from the substrate upto the top contact layer except the quantum well(QW) layers where small amount of compressive strain of 1.6% has been used. AlGaAsSb/AlAsSb has been used as the DBR material for achieving lattice matching with the substrate, and also for achieving higher refractive index contrast. The active material compositions have been chosen to obtain a peak gain at 1550 nm. The out come of this design is a top emitting VCSEL based on In P substrate using a different structure which is capable of producing 1550 nm light output and which can be constructed easily using widely used epitaxial techniques mixed with the MBE using digital alloy technique for the QW layers. The designed VCSEL is successfully simulated as an optical source, with an error free transmission of 70 km through a single mode optical fiber.The finalstructure of the VCSELis alsosuitablefor useinopticalICs.