IEEE Signal Processing - May 2018 - 11

special reports
John Edwards

The "Light" Side of Signal Processing
Research teams work toward a signal processing-enabled photonics future

researchers are investigating the
possibility of using light rather
than wires to provide communication across different parts
of a microchip. Yet achieving
this goal is a heady task, given
the fact that silicon, the material used to build chips, strongly
resists light emission.
Working on the project to create a light emitter and detector
that can be directly integrated into
silicon complementary metal-
oxide-semiconductor (CMOS)
chips are Yaqing Bie, an MIT
postdoctoral associate, and Pablo
Jarillo-Herrero, an associate professor of physics at MIT (Figure 1). The project leaders are
supported by an interdisciplinary
team including Dirk Englund, an
associate professor of electrical
engineering and computer science at MIT.
Figure 1. MIT researchers have designed a light emitter and detecSilicon-compatible light
tor that can be integrated into silicon CMOS chips. This illustration
sources
and detectors have been
shows a MoTe2 light source for silicon photonics.
studied for years, Bie notes. She
now believes that a device built
from
a
semiconductor material called
not
particularly
desirable,
since
excessiveEasing the microchip squeeze
2H-molybdenum
ditelluride (MoTe2)
ly
tight
wiring
can
lead
to
signal
leakage
Building faster computers requires
between components, hindering commusqueezing ever more transistors onto
could provide the answer. The ultrathin
nication between various chip parts. The
microchips. Steady downsizing also
semiconductor belongs to an emerging
phenomenon, known as the interconnect
demands microprocessor internal wiring
group of materials known as two-dimenbottleneck, threatens to impede, and perto be packed increasingly tightly. That's
sional transition-metal dichalcogenides.
haps even eventually block, microproces"Our technique is a CMOS-compatible
sor evolution.
method, and the most distinct feature
Addressing this concern, Massais the use of a two-dimensional crysDigital Object Identifier 10.1109/MSP.2018.2805738
Date of publication: 26 April 2018
chusetts Institute of Technology (MIT)
tal, which enables small footprints and

Ella Maru Studio/Mit

s the size and speed of many
conventional electronics technologies begin reaching their
practical limits, a growing number of researchers is turning their
attention to photonics and related
optical-based approaches to continue the push toward smaller,
faster, cheaper, and more innovative computer and communication devices.
Building on an already lengthy
and impressive track record, signal processing is now playing a
critical role in the development
of new optical communication
processes. Digital signal processing (DSP), for instance, is
widely viewed as the catalyst
for the "coherent revolution" that
paved the way for optical telecom
networks in the mid-2000s. Now,
signal processing is playing a role
in research that promises to lead
to denser and faster microchips,
more efficient networks, and other
important technology innovations.

IEEE Signal Processing Magazine

May 2018

Table of Contents for the Digital Edition of IEEE Signal Processing - May 2018