1060 nm GaAs VCSELs for Extended Reach Optical Interconnects in Data Centers
Licentiate thesis, 2018

The data centers of today are increasing in size and are built to accommodate strong data traffic demands while providing sustainably by having clients sharing resources under one roof. Their massive scale puts pressure on the server network topology and has incited a need for data transmission links that are energy efficient and capable to operate at high bit rates with reach up to a few kilometers. Optical interconnects (OIs) offer large bandwidth and low attenuation at long distances, and are therefore suitable for this task. The most commonly used OIs, with 850 nm GaAs-based vertical-cavity surface-emitting lasers (VCSELs) and multi-mode fiber (MMF), have a 25 Gb/s reach that is limited to a few hundred meters. However, the fiber chromatic dispersion and attenuation that limit the OI reach can be reduced significantly by increasing the wavelength of this very same technology. The upper limit of the GaAs-based VCSEL technology, with strained InGaAs quantum wells (QWs), is about 1100 nm.

With further improved OI performance, new hyperscale data center topologies can be realized and explored. This will lead to many more possible solutions in traffic engineering as well as for power management. 1060 nm VCSELs could open up for lane rates of 10, 25 and possibly 50 Gb/s over distances up to 2 km and help reach the Tb/s link speed aim of the Ethernet standard.

In this work we show that the 1060 nm GaAs VCSEL is a suitable light source for long-reach OIs by demonstrating its overall stable performance and capability of error-free data transmission up to 50 Gb/s back-to-back and 25 Gb/s over 1 km of MMF. These results stem from careful VCSEL design, including strained InGaAs QWs with GaAsP barriers, doped AlGaAs distributed Bragg reflectors, a short op-tical cavity and multiple oxide layers. We also show that the fabrication of such a device poses no increase in complexity and can be realized using standard processing techniques.

high-speed modulation


vertical-cavity surface-emitting laser



optical interconnect

chromatic dispersion


Kollektorn, MC2
Opponent: Nicolae Chitica, Finisar, Sweden


Ewa Simpanen

Chalmers, Microtechnology and Nanoscience (MC2), Photonics

1060 nm single-mode vertical-cavity surface-emitting laser operating at 50 Gbit/s data rate

Electronics Letters,; Vol. 53(2017)p. 869-870

Journal article

A. Larsson, E. Simpanen, J. S. Gustavsson, E. Haglund, E. P. Haglund, T. Lengyel, P. A. Andrekson, W. V. Sorin, S. Mathai, M. R. Tan, and S. R. Bickham. 1060 nm VCSELs for long-reach optical interconnects

Driving Forces

Sustainable development

Areas of Advance

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Subject Categories

Atom and Molecular Physics and Optics

Communication Systems

Nano Technology


Nanofabrication Laboratory

Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology: Technical Report MC2-389



Kollektorn, MC2

Opponent: Nicolae Chitica, Finisar, Sweden

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