All the abstraction levels of VHDL-AMS, properly used, would allow designing a whole system without using physical prototype. The virtual prototyping could replace physical prototyping, only the last prototype has to be fabricated. Work has to be done by using description modelling and predictive modelling of objects under study and by using modelling of the environment in which the system runs. Technological choices, dimensions, operating modes will be studied and compared. An example of parallel optical module will be taken for illustrating this purpose. The assembly within a single optoelectronic interconnect module of different components, including VCSEL and photodiode arrays, optical fibers and electronics implying electrical, optical, mechanical and thermal interactions, introduces new constraints in the conception phase and necessitates a new and different approach for modeling and simulation. A promising solution, when conceiving optoelectronic MOEMS is obtained by simulation with the multilevel language VHDL-AMS based on system component parameters and standards.