Analysis of evanescently-coupled pairs of spin-polarised vertical-cavity surface-emitting lasers

TL;DR

This paper develops a comprehensive model for arrays of coupled spin-polarised lasers, capable of handling arbitrary geometries and independent polarisation pumping, and analyzes the stability of solutions in double-guided structures.

Contribution

It introduces a general, flexible model for coupled spin-polarised lasers that includes independent polarisation control and applies it to double-guided structures with numerical analysis.

Findings

Increasing ellipticity of pumping enhances stability regions.

The model unifies existing single-cavity and coupled-mode models.

Numerical simulations reveal stability dependence on guide separation.

Abstract

A general model for the dynamics of arrays of coupled, spin-polarised lasers is derived, which is shown to reduce to both the spin flip model in a single cavity and the coupled mode model for a pair of guides in the appropriate limit. The general model is able to deal with waveguides of any geometry with any number of supported normal modes. A unique feature of the model is that it allows for independent polarisation of the pumping in each laser. The particular geometry is shown to be introduced via `overlap factors', which are a generalisation of the optical confinement factor. These factors play an important role in determining the laser dynamics. The model is specialised to the case of a general double-guided structure, which is then analysed and simulated numerically. For this case it is found that increasing the ellipticity of the pumping tends to enhance the regions where stable solutions are predicted in the plane of pumping strength versus guide separation.