Experimental and theoretical investigations on the modulation capabilities of a sample of vertical cavity surface emitting laser diodes for atomic vapour applications

This paper discusses various frequency modulation and intensity modulation capabilities within a sample of direct laser current modulated identical vertical cavity surface emitting laser diodes. The presented analysis is based on measurements of the spectral amplitudes as a function of the applied modulation power at a constant modulation frequency of 3.517 GHz. Their evaluation by Bessel function fits produces the three modulation parameters: frequency modulation index, intensity modulation index (via the a parameter) and the side band asymmetry of the first order side bands. The variation of the laser diode's modulation capability is discussed. It is found that the individual laser diodes show a significant variations in their modulation capabilities. Thus an experimental preselection of the laser diode is required to find laser diodes which are suit-able as a light source for atomic vapour applications, with special emphasis on a coherent population trapping-based scalar magnetometers.

Automated summary

This paper discusses the frequency modulation and intensity modulation capabilities of direct laser current modulated identical vertical cavity surface emitting laser diodes. The authors conducted measurements of spectral amplitudes and used Bessel function fits to evaluate modulation parameters such as frequency modulation index and intensity modulation index. The study found significant variations in modulation capabilities among individual laser diodes, which highlights the need for experimental preselection in applications such as scalar magnetometers.