A powerful deposition method used in the production of optical fibres is deposition via a microwave sustained plasma, the so-called PCVD process (Plasma-activated Chemical Vapour Deposition). Using a moving resonator, microwave energy is coupled into a substrate tube through which a mixture of gases is flowing. The general plasma modelling tool PLASIMO, developed at Eindhoven University of Technology, will be used for simulating the microwave plasma used by Plasma Optical Fibre. For this purpose, a new microwave energy coupling module was added to PLASIMO. As a first step, simulation results for an argon microwave plasma are presented.