Vertical cavity surface emiting laser for optical communication systems

The minimal cost, high efficiency and low power consumption of the Vertical Cavity Surface Emitting Laser (VCSEL) gives it an additional advantage when used in

applications like fibre optical communication systems to meet the growth of data

communication traffic. However, development of VCSELs working at longer wave lengths (1.3- 1.55 µm) has been limited by the inherent material problem making VCSELs longitudinal single-modes emitters. These problems among commonly used

fibre optic transmitters (Light Emitting Diodes) include: limited efficiency, limited

power output and incoherent light. Emitted power, threshold current and voltage

are the main device characteristics studied in this research. The basic functionality

of semiconductor lasers with improved output power performance is the main aim

of this work. Comparisons of growth techniques and material selection gives the

best material performance for nano optical sources used in optical communication

systems. A seven Quantum Well Indium Gallium Arsenide Phosphide (InGaAsP)

VCSEL structure that emits at 1550 nm is simulated and the following characteristics are analysed: Direct current and voltage (I-V) characteristics, light power against

electrical bias, optical gain against electrical bias, light distribution over the structure, output power, threshold current and gain profiles. The specification of the

material characteristics, the ordinary physical model settings, the initial VCSEL biasing, the mesh declarations, declaration of laser physical models, their optical and

electrical parameters were defined using Atlas syntax. Mirror ratings and Quantum

Wells are the two main parameters that were studied and analysed. Proper selection

of the emission wavelength and choice of material was done and a VCSEL with an

output power of 9.5 mW was simulated and compared with other structures.