Semi-analytical model for electrically injected GaAs nano-ridge laser diodes monolithically integrated on silicon

We present a semi-analytical model that can accurately explain the working principle behind the recently reported electrically injected In_0.2Ga_0.8As/GaAs monolithic nano-ridge lasers and more importantly show how the model can be used to study the effect of device parameters on the spectral behavior, the slope efficiency and the threshold gain. We show that mode beating between the fundamental mode and a higher order mode is fundamental in the operation of these lasers. Analytical expressions for codirectional mode coupling are used in developing the round-trip laser model. Results from analytical expressions are verified by comparisons with simulations and the model is supported later by measurement results.