The aim of this challenge is the demonstration of novel integrated laser sources on silicon. Different approaches will be explored. The characterization of existing technologies will first allow the production of specifications charts and device models necessary for architecture design. Second, innovative technologies will be investigated for ultimate integration on silicon.
FOTON-OHM will be the main actor of this challenge for the realization and characterization of novel laser sources on silicon. The Nanophotonics group at INL will also bring its expertise for the design of these microstructures. Strong interaction will take place with all the participants of the project on the requirements of modeled architectures and specifications of laser demonstrators.
FOTON-OHM’s positioning on the monolithic growth of III-V semiconductors on silicon appears now as a key asset for the integration of optical micro-systems on chip. Indeed, the use of the GaP-on-Si platform to build edge-emitting lasers and microdisk photonic devices would represent a drastic change of paradigm for optical integration and future microprocessor architectures with obvious advantages compared to existing technologies. GaP-on-Si devices operate in the datacom range and could even go down to the visible wavelength range, allowing for the realization of photonic devices twice or three times as small as InP-based components. GaP also features a thermal dissipation as good as silicon and above all, the monolithic growth of GaP on Si guarantees an optimal CMOS compatibility. However, this emerging field of research requires efforts on both the technological processing of GaP-on-Si devices and the investigation of their optical properties.
In the framework of the 3D-Optical-Many Cores project, FOTON-OHM will develop the first GaP-on-Si multi-frequency and single-frequency lasers to give a trend to the evolution of integrated photonics. Lasing will be studied with optical and electrical injection, at low as well as room temperatures. Multi-frequency lasing and frequency combs in large microdisks or edge-emitting lasers will be developed for their use as WDM sources. Particular attention will be given to the improvements of the new GaP-on-Si platform in terms of power consumption and thermal dissipation in the laser. This work requires a huge technological exploration since processing of GaP microstructures is not as mastered as in the case of GaAs or InP-based devices. Technological processes, including the etching of high Q-factor GaP microdisks, the coupling to passive waveguides and the electrical contacting will be under scrutiny. As an alternative way to achieve GaP based microlasers, and to avoid some technological risks, microresonators formed by only patterning Si layers will be investigated. In this case, the project will benefit from similar studies made by INL for InP/Si microlasers.
The investigation of these novel integrated laser sources will focus on energy saving considerations such as the coupling losses between active devices and waveguides, and energy costs per bit or per process in order to provide our partners a long-term outlook of silicon photonics. FOTON-Photonic Systems will share its expertise on laser physics, characterization of optical guides, and micro-components for transmission systems.