Modeling and measurement of spatial-hole-burning supplied to amplitude modulated coupling distributed feedback lasers

This work presents a theoretical and experimental study of the spatial hole burning (SHB) applied to phase-shifted amplitude modulated coupling (AMC) distributed feedback (DFB) lasers. Green´s function method is used in our model and a new development of this method allows us to calculate the side-mode power. A transverse model is developed allowing the calculation of the spatially dependent refractive index and coupling coefficient from the designed AMC-DFB laser structures. Modeling results show that the effective index variation, associated with that of the coupling coefficient, plays an important role in affecting the laser´s characteristics and has to be balanced to improve single-mode behavior. The SHB is studied experimentally by measuring the spontaneous emission radiated from a transparent window inside the electrode. The results clearly show, for the first time, the existence of a hole in the carrier density distribution due to the λ/4 phase-shift in a highly coupled laser. Both the measured and the calculated SHB are in agreement