This paper reports the design study of optical transducer for bioparticles detector integrated in Lab-on-Chip (LoC) system. Optical detector has been identified as potential device for real time detection of bioparticles because of its simple and compact structure, high sensitivity and easy of integration with microfluidic system. In this study, the absorbance detection using optical transducer is selected due to its label free nature and relatively simple implementation. The analysis work is focused on the characteristics of PIN photodetector simulated using Atlas and Athena software. It is observed that the lateral SOI based PIN photodiode exhibits the behavior of silicon PIN photodiode characteristics. The result also shows that Peak intensity at wavelength of 400nm was achieved and therefore, it is suitable to be used as bioparticles detector in UV/Vis spectrum.