Alexander Grabowski, Microtechnology and Nanoscience - MC2

​Title​: VCSEL Equivalent Circuits and Silicon Photonics Integration
Alexander is a PhD student at the Photonics Laboratory
Opponent will be: Dr. Mike Tan
Examiner and main supervisor: Prof. Anders Larsson

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The vertical-cavity surface-emitting laser (VCSEL) is a light source of
great importance for numerous industrial and consumer products. The
main application areas are datacom and sensing. The datacom industry
uses GaAs-based VCSELs for optical interconnects, the short-reach fiber
optical communication links used to transfer large amounts of data at
high rates between units within data centers and supercomputers. In
the area of sensing, VCSELs are largely used in consumer products such
as smart phones (e.g. face ID and camera auto focus), computer mice,
and automobiles (e.g. gesture recognition and LIDAR for autonomous

In this work, an advanced physics-based equivalent circuit model for
datacom VCSELs has been developed. The model lends itself to co-design and 
co-optimization ​with driver and receiver ICs, thereby en-abling higher data rate transceivers
with bandwidth limited VCSELs and photodiodes. The model also facilitates an understanding of how
each physical process within the VCSEL affects the VCSEL static and
dynamic performance. It has been applied to study the impact of carrier
transport and capture on VCSEL dynamics. The work also includes micro-transfer-printing 
of GaAs-based single-mode VCSELs on silicon nitride photonic integrated circuits (PICs).

Such PICs are increasingly used for e.g. compact and highly functional
bio-photonic sensors. Transfer printing of VCSELs enables the much-needed on-PIC integration
of power efficient light sources. The bottom-emitting VCSELs are printed above grating 
couplers on the PIC and optical feedback is used to control the polarization for efficient coupling
to the silicon nitride waveguide. Wavelength tuning, as required by the
bio-sensing application, is achieved by direct current modulation.
Keywords: Vertical-cavity surface-emitting laser, optical interconnects,
equivalent circuit, silicon photonics, light source integration, sensing.
Kategori Disputation
Plats: Kollektorn, lecture room, Kemivägen 9, MC2-huset
Tid: 2022-10-19 15:00
Sluttid: 2022-10-19 18:00

Sidansvarig Publicerad: on 19 okt 2022.