Simulation studies for mode profile analysis in single mode high power asymmetric large optical cavity laser structures

The simulation study for optimization of ridge waveguide parameters is carried out for designing of high power laterally-coupled Distributed Feedback (DFB) laser diode. The confinement factor, effective index and single mode analysis of GaAs/InGaAs single quantum well (SQW) high power laser diodes for emission at 976 nm have been investigated. Optimization of ridge width, ridge height and residual thickness of the underlying cladding layer, are required to achieve single and well confined mode. The confinement factor and effective index of these laser diodes with different residual thickness ranging from around 950 nm (shallow ridge waveguide) to 50 nm (deep etch ridge waveguide) are studied for different ridge widths. It is found from our simulation studies that the residual thickness of 447 nm can provide better flexibility in terms of coupling of the grating with the mode field. Thus, it serves as optimum dimension of ridge waveguide so that by incorporating grating in this structure we can achieve high power DFB laser diode.