The paper deals with the design of an micro-optical part of a WDM transceiver based on the circle volume holographic grating triplexer (VHGT) topology. The work is focused on detail description of the bidirectional micro-optical insertion system, especially on the coupling in the transmission direction of the WDM transceiver optical part. This micro-optical wavelength distribution system is imagine transmission system consisted of collimating cylindrical lenses set in the circle topology with the VHGT filter placed in the middle of the circle. The topology is described by ray matrices equations, calculated using analytic and numeric methods and optically measured. Considering simulation and measurement results of micro-optical insertion system the influence of these characteristics on ray path attenuation, diffraction efficiency and transceiver performance is estimated. The paper also discusses limits and conditions of the laser asymmetrical beam focus into the input/output optical fiber.