ABSTRACT We present a digital holography method for measuring the dispersive properties of semiconductor laser waveguides. The approach is based on low‐coherence off‐axis holography and enables the determination of wavelength‐dependent group delay and group index with high accuracy. In a wavelength range of 830–870 nm, the optical path difference is evaluated through the degree of coherence between object and reference waves. Compared to existing interferometric techniques, the method allows flexible measurements outside of integrated devices and avoids aliasing artifacts in spectroscopic approaches. Experimental results obtained with InGaAsP‐based semiconductor lasers show good agreement with theoretical models and demonstrate the suitability of this technique for dispersion characterization. In addition, the setup can be extended to measure other key laser parameters, such as carrier‐induced refractive index changes, offering a versatile tool for semiconductor laser analysis.
Zens et al. (Thu,) studied this question.