Three common types of VCSEL structures: (a) a top-emitting structure with proton implantation to
confine the current, (b) a selectively oxidized top-emitting structure to confine the optical modes
and/or the current, and (c) a mounted bottom-emitting selectively oxidized structure.
Courtesy of Princeton Optronics.
technology of low-dimensional semiconductors (semiconductor quantum wells,
wires and dots) and photonic nanostructures (micro- and nanocavities, photonic
crystals), as well as wafer-fused long-wavelength VCSELs.
BeamExpress SA, an EPFL spin-off
company, was launched to manufacture
long-wavelength VCSELs for telecom
applications. The company delivers low-power-consumption VCSELs with wavelengths ranging from 1250 to 1650 nm
and data rates up to 10 Gb/s.
“With traffic in optical networks increasing exponentially, the need for power
saving has emerged as a key constraint
limiting industry growth and profitability,”
said professor Eli Kapon, founder and
chief scientist at BeamExpress SA and
director of the Laboratory of Physics of
Nanostructures at EPFL.
“Due to the energy inefficiency and associated cooling requirements of existing
DFB and Fabry-Perot laser sources, the
physical footprint of higher speed and
higher density fiber optic transmission
equipment threatens to become impractical,” he added. “Further, electricity consumption in optical networks has become
a significant operating cost as well as an
VCSELs: The future
of optical transmission?
By their very nature, VCSELs are dra-
matically more energy-efficient optical
sources than either DFB or Fabry-Perot
lasers. A drawback, however, is that they
do not have very high single-mode power,
so they have to be used with amplifiers to
boost their power for high-speed commu-