Integrated tunable semiconductor laser geometry based on asymmetric Mach-Zehnder interferometers for gas sensing applications

A laser wavelength tuning mechanism featuring nested asymmetric Mach-Zehnder interferometers (AMZI) is proposed. In this scheme the optical path length unbalances are controlled with phase shifters, and provide with a tuning range in the order of few terahertz. The nested AMZI configuration allows for single mode operation of the laser by means of Vernier effect, and limits the required number of control elements. Therefore the complexity and the overall length of the integrated laser cavity can be reduced. The preliminary laser chip designs for the COBRA InP active-passive photonic integration platform along with some modeling results will be presented.