Multilayer Vertically Integrated Cavity-less Comb Source

We propose a cavity-less comb source for PNT and optical communications on a photonic integrated circuit using specialized multilayer material with low deposition temperatures to improve the manufacturing process. PICs provide the promise of greatly reducing the SWaP of complex photonic systems; however, PIC materials are often specialized into handling certain features. For example, silicon handles some active components but has higher losses. Silicon nitride is incompatible with active materials but has superior loss properties and performs well with passive components like couplers. Cavity-less comb architectures require a mix of active, passive, and sometimes nonlinear components. The integration of these types of components offers a challenge in traditional PIC materials. Our unique materials enables layers to be grown on top of other materials without disrupting the structure of the lower layer materials such that each layer on the chip can perform a specific unique function optimized for the required components of the cavity-less comb source. We anticipate our proposed architecture and multilayer approach to enable more flexibility in repetition rates (1 GHz-10 GHz) and bandwidths (~5nm) beyond the current state of the art of these cavity-less comb sources (~5-10 GHz, 2.5nm).