Wavelength-change characteristics of semiconductor lasers and their application to holographic contouring

Abstract

The dependence of double-heterostructure AlGaAs semiconductor laser wavelength on injection current and temperature was investigated by means of a Michelson interferometer. The lasers operated in a single longitudinal mode at 790 nm, permitting them to be applied to two-wavelength holographic contouring. Continuous change and discontinuous change by mode hopping were observed. The wavelength was continuously tunable by variation of injection current and temperature at rates of 0.0045 nm/mA and 0.070 mm/°C, respectively. Discontinuties in wavelength change were observed to be integer multiples of the longitudinal mode spacing. Holographic contour fringes were interpreted given the measured variation in wavelength.