Innolume, a leading provider of quantum-dot (QD) laser diodes and
modules covering the 1050 nm to 1320 nm spectrum, today announced that
it will begin sampling its ground-breaking semiconductor laser, the
InnoComb. It is the world’s first diode laser
to emit tens to hundreds of pure, low-noise colors (comb spectrum) from
a single laser cavity. This new class of lasers will facilitate a
wavelength-division multiplexing (WDM) revolution in short-reach, high
bandwidth optical interconnects. WDM was previously restricted to
telecom due to the costly laser arrays required. Today, powered by a
single InnoComb, WDM can finally be harnessed for low-cost, short-reach
computer interconnects.
Following last year’s demonstration of the
first broad-spectrum Fabry-Perot (FP) laser (>
70 nm, Opt. Lett., 2007, 32, pp. 793-795), Innolume
dramatically reduced relative intensity noise (RIN) of each spectral
line, culminating in the diode comb laser as a practical computer
communications source. “This laser innovation
offers increased integration and functionality at reduced size and cost,
i.e., using cavity resonance with QD gain behavior to replace laser
farms or integrated laser arrays,” stated
Innolume’s President and CEO, Jürgen
Kurb. He noted further, “Space- and
cost-efficient WDM systems are enabled for the first time, offering new
datacom opportunities with respect to cost, power and reliability.
Additionally, the comb laser simplifies system design by virtue of all
channels moving in unison with shifting temperature.”
InnoComb is a single FP laser emitting many lines/wavelengths/channels
(longitudinal cavity modes) with nearly the same power on each. Innolume
has demonstrated 10 mW of power per channel over 16 channels, and >1
mW/channel over 100 channels. Channel spacing is currently available
from <50 GHz to 140 GHz (<
0.28 nm to 0.8 nm) centered at any wavelength between 1250 nm and 1320
nm. For datacom, the comb laser’s channels are
separated (demultiplexed), modulated externally at ≥10
Gb/s, and multiplexed for single-fiber transmission. External modulation
on 16 comb channels was demonstrated by HHI, Berlin (Electron. Lett.,
6th Dec. 2007, v43, 25, pp. 1430-1431),
with error-free transmission (BER<10-13)
due to exceptionally low RIN (~0.1%) on each
lasing line. “The diode laser as a
multiple-wavelength source in high speed communication systems has been
something of a ‘holy grail,’
but noisy longitudinal lasing modes in quantum well FP lasers made them
a ‘no-go.’ In
contrast, the comb lasers we tested from Innolume show eye diagrams for
each line comparable to the best single-frequency ECL lasers, thus
opening great opportunities for efficient 1300 nm WDM communication
systems based on a single laser,” said Dr.
Norbert Grote, Head of the Laser Group at Fraunhofer
Heinrich-Hertz-Institut, Berlin.
According to Prof. Zhores Alferov, Ioffe Institute, St.Petersburg (2000
Nobel Laureate for the double heterostructure—the
basis for diode lasers), “Ioffe graduates at
Innolume have invented a new class of semiconductor lasers based on
fundamental behaviors of Quantum Dots. With their enablement of comb
laser diodes, Quantum Dots have found their key differentiator from
conventional Quantum Wells, with huge potential for practical
implementations. Integration has been a major driving force for the
electronic industry, and now Quantum Dot technology puts us on the same
road, making it possible to embody hundreds of CW lasers inside a single
diode laser cavity.”
“However great a technology is, it always
comes down to cost,” commented Innolume
Senior Optical Engineer, Dongliang Yin. “Our
single InnoComb device relies on conventional FP edge emitter
fabrication processes, providing a highly-leveraged alternative to
proposed arrays of 16, 32, or even 100 DFB lasers. Integrated DFBs can
cost 10x more per laser than a single FP comb. The tradeoff is our need
for an additional demultiplexer, an integrated AWG, instead of multiple
lasers. Therefore, QD comb lasers provide an attractive light source for
commodity applications including ubiquitous WDM for short-to-medium. In
the long run it also brings the right economics to future chip-to-chip
optical communication. As Silicon Photonics technology matures to the
point of economically managing light between processor chips, a single
comb laser ‘power supply,’
either off-chip or bonded to the silicon, will drive the many optical
channels necessary for TB/s interconnects.”
In summary, conventional quantum well diode lasers with or without
mode-locking remain too noisy to be practical comb lasers for high speed
communication. Innolume’s quantum dot
materials and laser designs overcome this deficiency for the first time,
permitting novel and timely applications. Now the industry can migrate
the bandwidth advantages of WDM from expensive telecom systems to very
low-cost, short reach transceivers, alleviating cost/power/weight/volume
issues with server and backplane interconnects. Ultimately, the comb
laser can drive high speed WDM interconnects in a photonics switching
layer “under”
future multi-core computer processors. According to architectural
analyses by top-tier computer companies and academics, this offers a
100x power advantage over projected electronics performance.
About Innolume (www.innolume.com)
Originally spun-out of the Ioffe Physico-Technical Institute in St.
Petersburg, Russia to its fabrication facility in Dortmund, Germany,
Innolume (formerly NL Nanosemiconductor) offers laser semiconductor
chips and modules at the specific wavelength range of 1.1–1.3
microns for medical, industrial, communications and computer markets.
Its quantum dot technology and proprietary design concepts enable
tangible improvements in cost, performance and quality of compound
semiconductor devices used in optoelectronics.
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