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Proceedings Paper

980-nm VCSELs for optical interconnects at bandwidths beyond 40 Gb/s
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Paper Abstract

The copper-induced communication bottleneck is inhibiting performance and environmental acceptance of today's supercomputers. Vertical-cavity surface-emitting lasers (VCSELs) are ideally suited to solve this dilemma. Indeed global players like Google, Intel, HP or IBM are now going for optical interconnects based on VCSELs. The required bandwidth per link, however, is fixed by the architecture of the data center. According to Google, a bandwidth of 40 Gb/s has to be accommodated. We recently realized ultra-high speed VCSELs suited for optical interconnects in data centers with record-high performance. The 980-nm wavelength was chosen to be able to realize densely-packed, bottom-emitting devices particularly advantageous for interconnects. These devices show error-free transmission at temperatures up to 155°C. Serial data-rates of 40 Gb/s were achieved up to 75° C. Peltier-cooled devices were modulated up to 50 Gb/s. These results were achieved from the sender side by a VCSEL structure with important improvements and from the receiver side by a receiver module supplied by u2t with some 30 GHz bandwidth. The novel VCSELs feature a new active region, a very short laser cavity, and a drastically improved thermal resistance by the incorporation of a binary bottom mirror. As these devices might be of industrial interest we had the epi-growth done by metal-organic chemical-vapor deposition at IQE Europe. Consequently, the devices were fabricated using a three-inch wafer process, and the apertures were formed by proprietary in-situ controlled selective wet oxidation. All device data were measured, mapped and evaluated by our fully automated probe station. Furthermore, these devices enable record-efficient data-transmission beyond 30 Gb/s, which is crucial for green photonics.

Paper Details

Date Published: 7 February 2012
PDF: 9 pages
Proc. SPIE 8276, Vertical-Cavity Surface-Emitting Lasers XVI, 827605 (7 February 2012); doi: 10.1117/12.908466
Show Author Affiliations
W. H. Hofmann, Technische Univ. Berlin (Germany)
P. Moser, Technische Univ. Berlin (Germany)
P. Wolf, Technische Univ. Berlin (Germany)
G. Larisch, Technische Univ. Berlin (Germany)
W. Unrau, Technische Univ. Berlin (Germany)
D. Bimberg, Technische Univ. Berlin (Germany)
King Abdulaziz Univ. (Saudi Arabia)

Published in SPIE Proceedings Vol. 8276:
Vertical-Cavity Surface-Emitting Lasers XVI
Chun Lei; Kent D. Choquette, Editor(s)

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