Periodic Reporting for period 2 - NARIoS (Nano-Ridge Engineering for Densely Integrated III-V Lasers Directly Grown on Silicon)
Período documentado: 2022-03-01 hasta 2023-08-31
Although Silicon Photonics, i.e. using mature technologies from the CMOS-industry for realizing complex photonic ICs, progressed enormously, with industrial uptake by the biggest electronics manufactures, its real breakthrough, in e.g. large volume consumer applications or very short interconnects, is hampered by its lack of a true waferscale optical source. Combining aspect-ratio trapping, to suppress defects, and nano-ridge engineering, to shape the resulting material, we have developed a powerful platform to integrate direct bandgap III-V semiconductors on standard silicon wafers, using truly waferscale processes. The exceptionally high quality of this material was confirmed through morphological studies, gain and lifetime measurements and the demonstration of lasing under optical pumping. For practical applications, electrical injection is key though, which thus far has been elusive as the dimensions of the resulting GaAs/InGaAs nano-ridges are too small to directly apply electrical contacts without introducing unacceptable losses. Therefore, NARIoS’ primary objective is to propose device concepts that overcome the trade-off between optical confinement and efficient current injection. We aim at the demonstration of electrically injected microcavity lasers for low-power applications and the demonstration of a novel class of mW-lasers with in-plane or out-of-plane emission, exploiting the possibility to grow highly uniform arrays of these nano-ridges. These device-oriented objectives are complemented by two transversal objectives: development and extensive characterisation of InGaAs nano-ridges for extending the lasing wavelength and exploiting novel concepts from recent literature to design lasers resilient to optical feedback and/or exhibiting lasing in a single coherent spatial mode.
Within the context of the NARIOS project as a whole, we are working on multiple subprojects, each focussing on a particular device implementation exploiting the nanoridge platform. In each case we started with advanced optical modelling of the proposed device implementation, both using numerical tools such as FDTD and by building analytical models. The latter are important as they allow to carry out a much more in-depth optimisation, scanning over a much broader parameter space. Next, we carried out an optical characterisation of the proposed devices, both under optical and electrical injection. For the vertically emitting devices, this required building a new optical setup for characterising both the near and far field emission pattern. We showed for the first-time clear laser operation in such devices. The electrically injected devices were tested in detail in terms of RIN, linewidth, emission spectrum and static properties. For the photonic crystal based micro lasers, a thorough optimisation of the etching process has been carried out. To quantify the damage induced to the material by this etching process, we set up a time resolved photoluminescence setup and measured the impact on PL lifetime by the etching process. Finally, we also initiated a new subproject, in which we fabricated waveguide integrated detectors based on alternative active materials such as colloidal quantum dots and 2D-materials.
By the end of the project we aim to have demonstrated for the first time:
- A vertically emitting laser based on the nanoridge platform, and an associated model
- An electrically injected microlaser, based on the nanoridge platform
- An in depth characterisation of and an analytical model for bimodal nanordige lasers
- Long wavelength (beyond 1600nm) waveguide detectors integrated on a silicon photonics platform, based on nano materials
Each of these objectives go beyond state of the art
- A vertically emitting laser based on the nanoridge platform, and an associated model
- An electrically injected microlaser, based on the nanoridge platform
- An in depth characterisation of and an analytical model for bimodal nanordige lasers
- Long wavelength (beyond 1600nm) waveguide detectors integrated on a silicon photonics platform, based on nano materials
Each of these objectives go beyond state of the art