We present work towards a visible wavelength tuneable external cavity laser (ECL) on a silicon nitride platform working around 640 nm. A ring resonator Vernier structure on the photonic integrated circuit (PIC) provides delayed feedback with spectral filtering and tuning. Gain is provided by a reflective semiconductor optical amplifier (SOA) grown on a GaAs substrate and integrated by pick-and-place flip-chip assembly. In a novel coupling scheme, the 1-dB in-plane placement tolerance is relaxed by a multi-mode edge-coupler to ± 2.6 µm in the direction parallel to the SOA edge and to displacements up to 3.5 µm from the PIC interface along the SOA's optical axis. Pedestals defined in the PIC guarantee vertical alignment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.