Characterization and wavelength control of DBR-based dual-wavelength lasers

Multi-wavelength lasers - i.e. devices that can emit simultaneously on different wavelengths - represent an interesting opportunity for terahertz and telecom applications. In this context, implementing such devices with a generic process appears to be a key requirement to fully benefit from the development of these new platforms for Photonic Integrated Circuits (PICs). However, the genericity of the process comes at the cost of certain limitations in terms of design or performances.

Through InP Multi-Project Wafer (MPW) runs, we have developed compact dual-wavelength laser (DWL) designs by taking advantage of the properties of Distributed Bragg Reflectors (DBRs). We use two detuned DBRs as narrow-bandwidth frequency-selective mirrors on one side, and, on the other side, we close the laser cavity with either a broad bandwidth multi-mode interference reflector (MIR) or a third DBR with a broader bandwidth than the first two. While each design successfully shows dual-wavelength emission, their emission properties significantly differ from one to another.

In this contribution, we characterize the different laser designs and focus on the DBRs themselves. In particular, we study their characteristics when a current is applied or the temperature is changed. Next, we investigate and analyse their impact on the emission properties of the dual-wavelength lasers. Thus, we provide further insight on the relevance and potential of the proposed DWLs and highlight key points for the tailoring of these devices for a given application.