HyperLight demoes hybrid integrated transmitter with DFB laser on LiNbO₃

15 Dec 2021

Partnership with Harvard and Freedom Photonics paves way for such high-power lasers.

HyperLight, a developer of thin-film lithium niobate photonic integrated circuits for datacom, analog, and quantum applications, has demonstrated, together with collaborators from Harvard University and Santa Barbara, Ca.-based Freedom Photonics, a new process of integrating high-power lasers on thin-film lithium niobate platform.

This hybrid platform has enabled the first high optical power transmitter chip consisting of an electrically pumped DFB (distributed feedback) laser integrated with HyperLight’s high-speed thin-film lithium niobate intensity modulator capable of operating at 60 mW output power and beyond 50 GHz electro-optic bandwidth.

HyperLight says that the integration of optical components and other functions into a large-scale photonic integrated circuits are “critical in enabling next-generation digital and analog communication applications by reducing the total components cost.” The work is described in a paper on arxiv.org.

The cost is reduced by the need for fewer discrete parts, less packaging and assembly steps, and lower power consumption. The commonly-used integrated photonics platforms based on materials such as silicon and indium phosphide have not been able to meet the power, cost, and performance requirements of components and network providers due to the intrinsic limitations of the material, say the developers of the new approach.

Superior optical properties

Thin-film lithium niobate, due to its superior optical properties, has emerged as an ideal photonics platform for the realization of high-performance chip-scale optical systems. The partners employed DFB lasers for integration with thin-film lithium niobate because of their low cost, small footprint, and large output powers exceeding 100 mW.

Using only passive-alignment and flip-chip thermo-compressive bonding, the DFB lasers emitted approximately 60 mW (17.8 dBm) of optical power into the thin-film lithium niobate waveguides. This will enable new architecture such as large arrays of high-power transmitters as well as unprecedented performance in optical links.

Mian Zhang, CEO of HyperLight, commented, “We are excited to be a part of this remarkable demonstration of the hybrid integration capability of the thin-film lithium niobate platform with other critical optical components.”

“The traditional bulk lithium niobate solutions are widely deployed but are limited in performance and applications due to the lack of integration. Our miniaturized thin film integrated solution combines the superior proven material property of lithium niobate with scalable silicon semiconductor processes at low cost,” Zhang added.

“Hybrid integration of key active high-performance components such as DFB lasers with thin film lithium niobate results in best in class performance combined with low cost which opens up a lot of possibilities for those innovators who are looking into lower power consumption and lower cost solutions for optical networks beyond 800G and 1.6Tb/s.”

This development is part of the US Defense Advanced Research Projects Agency (DARPA)-funded program Lasers for Universal Microscale Optical Systems (LUMOS) which aims to bring high performance lasers and amplifiers to manufacturable photonics platforms through heterogeneous integration of diverse materials.