A tunable integrated long wavelength laser for gas detection

We are designing an integrated tunable single-mode laser for gas detection, in particular breath analysis. We aim for the long wavelength range at around 2 µm, where compact sources are still missing. This process includes adapting the existing building blocks at the telecommunication wavelength of 1.55 µm and incorporate their functionality to longer wavelengths. Building blocks have to be active (semiconductor optical amplifiers/SOA) and passive (waveguides, bends, multimode interference devices/MMIs, phase modulators) to enable lasing and tunability. First designs are made at 1.55 µm and later ported to 2 µm. Chips will be processed in the JePPIX/COBRA platform. Cold cavity simulations have been done using circuit simulators. Transmission characteristics and layout are shown on the poster. The tested structures consist of nested and serial Mach-Zehnder and Michelson interferometers and provide sufficient means to operate in single mode regime. Phase shifters in the different arms of the interferometer allow for tuning and selecting the desired wavelength. Multiple layouts can be compared once processed and the best one for 2 µm can be determined.