The Future with Nano ICT—It's right there

Interview

Opening up New Possibilities in Communications
using Nano-technology

Information and communications networks have become essential for our lives
in society. However, as systems become
faster and increase in capacity, we cannot
ignore the increasing power consumption
and heat generated, and new technicalbreakthroughs are needed urgently. A development promising for answers to theseissues is the appearance of nano-technology materials and devices. We spoke with Dr.
Akira OTOMO, Director of Nano ICT Laboratory, Advanced ICT Research Institute.

■Nano-technology in informationand communications

Akira OTOMO

Director of Nano ICT Laboratory,
Advanced ICT Research Institute
After completing a doctoral program, hejoined the Communications Research Laboratory (currently NICT) in 1996. Engaged
in research on applications of molecular
photonics and nano-photonics for opticalcontrol technologies. Current position held
since 2011. Ph.D.

─ We often hear about "nano-technology"
as an advanced technology that gets a lotof attention, but beyond "the world of theextremely small," it is difficult to form animage of exactly what it is, or how it is related to information and communications
technology.

■Two fields producing innovative
hardware─ Can you describe specific examples of
the research you are doing?
OTOMO We are working on two main research themes.
The first is organic materials. In organicmaterials, π electrons in the molecules are resonant with the optical electromagnetic fields,
so they have faster, more efficient photoresponsivity than inorganic materials. However,this feature is affected by molecular structure
and arrangement, so design, control and synthesis at the molecular level—of just a few
nanometers—is necessary (Figure 1). Our
Organic Nano-Device Group handles this area.
The other theme is superconducting materials. As you know, superconductivity is thephenomenon by which the electrical resistance of certain materials drops to zero be-

OTOMO It's true, the word 'nano-scale' alone
might not give a clear image of what we'retalking about. A nanometer is a unit that is one
billionth of a meter. If I say that one tenth of ananometer is on the scale of atoms and several
nanometers is on the scale of molecules, doesthat convey how tiny this is?
The Nano ICT Laboratory deals with applying materials and processing technologies
at these scales in the field of information andcommunications technology. We are conducting R&D on innovative ICT hardware thatwould not be possible by only making small
advances of existing technologies. Nano-technologies open up possibilities for devices thathave much higher performance and efficiency,
and are smaller than ever before. This has hugebenefits for network infrastructure, which continues to grow in scale.

Figure 1 Synthesis of new organic molecularmaterials2NICT NEWS JAN 2016low a particular temperature. There is greatpotential for devices that make use of uniqueproperties, such as perfect conductivity andflux quantization, which occur in that state. To
develop such superconducting devices, atoms
must be deposited to thicknesses in the rangeof ten nanometers, requiring technologies fornano-processing and forming thin films. Our
Superconductive Device Group handles thisarea.

■Results coming into practical use
─ Are there any technologies from yourR&D that are at or near the stage of practical application?
OTOMO One device that is particularly oriented to practical use is our superconducting
nanowire single photon detector (SSPD)(Figure 2), which was developed based on niobium nitride (NbN) thin film deposition andnanowire fabrication techniques from our superconducting device research. This photon
detector has higher performance than the avalanche photodiodes (APD) that are currently
in wide use and it is becoming a key device
for quantum cryptography communication
systems in the field of information and communications.
The SSPD also promises to have broad influence in fields other than information andcommunications. Dramatic improvement inperformance and speed can be expected infields such as fluorescence microscopes andlaser ranging technologies, by replacing thecurrent semiconductor devices with SSPDs.
We are also planning to make organic electro-optic (EO) polymers more practical. These
are needed for optical modulators and othercomponents in optical communications, whichforms the foundation for information andcommunications technology. We can increase
speed and save energy by using efficient organic materials. We have already achieved
modulation at speeds exceeding 100 GHz.
Conventionally, organic materials have had
the disadvantage of being susceptible to environment compared to inorganic materials, but
we are developing technologies to make themmore practical, such as developing heat-resistant EO polymers, and protecting materials
from surrounding oxygen and water by covering the surface with a layer of atoms of an
inorganic material.
NICT overall is also promoting researchon terahertz (THz) technologies, and organic
materials are having a great influence on thisfield as well. The frequencies are higher than
the gigahertz (GHz) band, where modulators
generally operate, but the interactions are basically the same. Thus, using the materials anddevices we have created for ultra-high-speed
optical modulators will enable us to implement
THz generators that are more efficient andcompact than before. This is another theme weare pursuing vigorously.

Figure 3 High-performance organic EO material to
go on the market■Strength in an R&D system integrated
from materials to devices
─ It sounds like you will be producing
some very interesting results in the future.
What are your laboratory's particular features or strengths, in terms of research organization?
OTOMO Generally in materials research,devices are divided into their own specialties,and usually they don't cooperate well. But in
our Nano ICT Laboratory, we synthesize ourown materials, and have integrated development from instrumentation to design and device development. As such, we have a goodunderstanding of the characteristics of thematerials when we create a device, and we cango back to basic principles for ideas in finding solutions to whatever issues we meet. We
are getting many inquiries about collaborative
research and are planning to sell the materials
themselves for an appropriate price, in order toexpand the foundation for R&D (Figure 3).
Of course, the market for what we areworking on will be small initially, and there
are many issues, but considering the future of
information and communications technology,
there should be strong demand. We feel our responsibilities in this area strongly.

Figure 2 Inside of the superconducting nanowire
single photon detector (SSPD) system

NICT NEWS JAN 20163