Design and performance of a vertical cavity surface emitting laser based on III-V quaternary semiconductor alloys for operation at 1.55 μm

A highly efficient Vertical Cavity Surface Emitting Laser (VCSEL) has been designed and fabricated for operation at a wavelength of 1.546 μm. The device design incorporates optimized Bragg mirrors with minimized number of periods. The present structure employs quaternary III-V semiconductor alloys with GaInAsP as the active layer and AlGaInAs/InP multilayer stack as the Distributed Bragg Reflector (DBR). The material parameters of the quaternary alloys including index of refraction and bandgap energy are calculated over the entire composition range. The difference in the indices of refraction between AlGaInAs and InP alternating layers is found to be 0.46 resulting in a significant reduction of the number of DBR layers. The MBE technique is employed for the epitaxial VCSEL structure growth and the selective oxidation of AlInAsP single layer is used to form the current confinement aperture. The VCSEL gain performance has been calculated and measured, resulting in the experimental threshold current of about 3 mA and the output power of 1 mW