The design of hybrid electro-optical systems needs to address the issue of signal integrity. In the area of electrical interconnects the input/output buffer information specification was introduced. To define a similar specification for optical interconnects an analytical model for vertical cavity surface emitting lasers is developed. It is based on the known solution of the Lotka-Volterra differential equations, which are related to the rate equations describing the behavior of lasers. The parameters of this analytical model directly describe the dynamic behavior of vertical cavity surface emitting lasers and they share many features with the input/output buffer information specification as they can be provided in a tabulated form and are partly accessible to measurement.