Detailed experimental study of high-frequency self-pulsation domains in multi-section DFB-lasers

We establish an extensive experimental registration technique to study the dependence of the pulsation in a three-section DFB-laser. The common feature of continuous pulsation domains is highlighted and the impact of geometrical parameters is investigated. The measurements allow the quantitative determination of pulsation frequency, rf-amplitude, wavelength and optical power at the same time. Based on a reproducible fabrication technology, we found that the phase section plays the main role to control the self-pulsations. The phase section also exhibits a negative reflectivity slope necessary for dispersive Q-switching like the reflector. Phase section lengths in the range between 200 and 500 mu m are very well suited. The length of the reflector section is not very critical Devices with 90 mu m and 200 mu m long reflectors work well. Other parameters that are responsible for the frequency of self-pulsations are determined by the heterostructure and must be optimized separately.