A new type of the light modulated DSC was constructed. Optical fibers are used to separate the light source from the furnace. The sample can be handled accurately because the lamp and the intensity modulator are not above the furnace. Quality of the measured signal is much improved by extracting the analog signal from the electronic circuit board in the commercial DSC. Light intensities of the sample and reference sides are controlled independently from each other. A method to compensate for the asymmetry of the thermal system utilizing the independent control of the light intensity is proposed.