Tunable InP-based buried heterostructure lasers with vertically integrated Mach-Zender interferometer (VMZ)

We report on the first realization of a novel VMZ type laser diode and investigate technological performance implications as well as the theoretical tuning characteristics. In contrast to previously realized VMZ lasers, the active layer and the tuning layer are incorporated in different waveguides. This enables a larger tuning range but leads also to a stronger dependence of the spectral selectivity on the tuning current. Owing to its buried heterostructure fabrication technology, the performance of realized devices is limited mainly by leakage currents. Therefore, the electrical loss mechanisms occurring at growth interfaces in chemical beam epitaxy (CBE) are treated in detail.