Choice of modulation parameters in photothermal-modulation laser diode interferometer

In the laser diode interferometer with a photothermal wavelength modulation which is used for optical fine measurement, intensity fluctuations of light source cause measurement errors through the fluctuations decrease greatly as compared with the injection current modulation of wavelength. In this paper, we investigated the effect of photothermal modulation parameters of wavelength on the intensity fluctuations of light source. Choosing appropriate photothermal-modulation parameters, we measured microdisplacements of object with a high measurement accuracy.