Integrated Laser-on-Silicon Photonics Gets a Boost from DARPAJanuary 12, 2021 by Luke James
Partially funded by DARPA, Tower Semiconductor is creating a new foundry process for integrated-laser-on-silicon photonics.
Recent innovations in integrated photonics have allowed engineers to dramatically reduce the size of optical components and fit several elements on silicon chips to produce photonic integrated circuits (PICs).
Instead of electrons, PICs use photons, the massless particle that represents a quantum of light (i.e., they use light instead of electricity). These photons are able move at the speed of light with almost zero interference from other photons, making PICs much faster and more efficient than conventional circuits based on electrons.
Laser Integration on Silicon
When combined with lasers, these PICs hold the potential to replace large and expensive optical systems, which currently find themselves being used in applications in key areas like manufacturing, sensing, and communications.
Example of a PIC that uses light instead of electricity. Image used courtesy of Edmund Optics
Integrating lasers with silicon also brings with it many benefits, including an increase in the density of lasers, a reduction in coupling losses between the laser and the photonics, a reduction in the number of components required, and smaller, simpler packages.
Due to the differences in the properties of lasers and PICs, however, it’s difficult to combine them onto the same platform. This limits the integration potential and the benefits that could come with it.
DARPA's LUMOS Program
To attempt to solve this problem, Tower Semiconductor has announced that it is participating in the Defense Advanced Research Project Agency’s (DARPA) LUMOS program in a bid to create a semiconductor foundry integrated-laser-on-silicon photonics process.
The Lasers for Universal Microscale Optical Systems (LUMOS) program has been designed to bring high-quality lasers to photonics platforms with ease. According to DARPA, LUMOS will address several commercial and defense applications for advanced photonics platforms by focusing efforts across three technical areas.
DARPA has already reached out to a number of semiconductor manufacturers and university researchers to participate in LUMOS. Image used courtesy of DARPA
The first LUMOS technical area involves Tower Semiconductor and the SUNY Polytechnic Institute, which will bring high-performance lasers and optical amplifiers into advanced domestic photonics foundries.
Tower Semiconductor's Part
Under this partnership, Tower Semiconductor aims to demonstrate flexible, efficient on-chip optical gain in their photonics processes. This may enable next-generation optical microsystems for key communications, computing, and sensing applications.
To achieve this, Tower Semiconductor will combine high-performance III-V laser diodes with its PH18 production silicon photonics platform. When ready, multi-project wafer (MPW) runs will be coordinated with the new process.
Tower Semiconductor offers a Multi-Project Wafer (MPW) shuttle program. Image used courtesy of Tower Semiconductor
The company estimates that initial versions of the process development kit (PDK) will be ready this year and will include laser and amplifier blocks.
Other technical areas of LUMOS will look to develop high-power lasers and amplifiers on fast photonics platforms for microwave applications and create precise lasers and integrated photonic circuits for visible spectrum applications.