The capability to model optical instrument prior to detailed design and analyses is very powerful tool that can save schedule time, instrument implementation costs, and gives great insight into many facets of optical instrument development effort leading to better innovations. Optical engineering software has the capability to model the completed self-mixing interferometer (SMI) from laser diode as a light source through the optical components up to the photodetector. The peculiarity of the SMI is that the sample under test has to be included in the optical scheme consideration as a reflective optical component. Every time changing object the optical properties of SMI must be optimized. Modeling of SMI which consists of off-the-shelf components like as an aspheric lens and anamorphic prisms was carried out. The first step in modeling an optical system was creating an accurate geometrical model. Collimated beam is important feature for vibration measurements as object displacement leads to change the value of object surface reflection caused by no good collimated laser beam. The purpose of analyses and optimization is the modeling of the SMI optical system which gives collimated beam of laser diode. Optical soft analyses like 3D layout, spot diagrams, relative illumination and coherent irradiation have been under consideration. Another intended benefit of the SMI modeling by optical soft is the signal detection and processing area. Based upon the power, irradiance, or other radiometric based measurement the SMI can provide signal level information.