Hi, thanks for tuning into Singularity
Prosperity. This video is the eighth in a
multi-part series discussing computing
and the first discussing non-classical
computing. In this video, we'll be
discussing what optical computing is and
the impact it will have on the field of
computing. The speed of computation is
limited by two factors: how fast
information can be moved, data transfer,
and how fast that information can be
processed, data computation. Currently,
this limit is imposed via the properties
of electricity, the flow of electrons.
There is however another field of
computing focused on a different
paradigm, optical computing, also called
photonic computing. This refers to the
use of light, the flow of photons, for use 
in computing and electronics. Light, more
specifically infrared light with
wavelengths around 1500 nanometers, is
currently used for data transfer and
communication over long distances, this
is referred to as fiber optics. Beyond
long distance data transfer, the
principle of using light for data
manipulation extends to computing as well:
I work in the area of fiber optics,
specifically building new types of logic
that can compute all optically as
opposed to electronically. I'm basically
taking fiber optics and putting it into
your computer to do logic and CPU
components. The results of my research
will be increasing the bandwidth of
computers from gigahertz speeds to
terabit per second speeds, which is 
1000 times greater!
This type of advancement won't be in
your computer tomorrow, but it's the
building block to creating the next
generation of technology, which you will
see years down the road.
Unlike the longer infrared wavelengths
needed for long distance communication
to avoid signal degradation, the light
used for computation will be in the
visible part of the electromagnetic
spectrum, with wavelengths in the range
of 450 to 700 nanometers. This is because
when working with small scale distances,
signal degradation isn't issue but
computing speed is. Electronic
circuits operate based on millions,
billions of switches, that alternate
between an on and off state, this
switching process alone induces latency.
Photonics simply uses wave propagation,
the interference pattern of waves, to
determine a result.
This allows for instantaneous
computations, without the delay induced
by switch latency: Optical computing is
actually the science or the art to use
photons instead of electrons to do
computation. So what we do here is we try
to process data signals in the optical
domain instead of the electronic domain,
and then that's actually what is cool
about optical computing, because we
process data while it's traveling, we
don't stop the data movement nor the data
flow and we process it. This is a bit
similar to what we do in memory driven
computing, where we bring the processor
closer to the memory. Here we bring the
processing closer to the data while it's
in-flight. So if you have to compare
that with what we do today, every
time we send or receive information
from an optical fiber then we need to
convert it between the electronic domain
and the optical domain, what is key here
is that this technology allows us to
avoid that. So what we have to make or
what we have to build when we do optical
computing is a logic gate, and to make
that using tabletop optics like the one
that you see over here, with a lot of
lenses and mirrors and so on - that
becomes really really difficult at a
macroscopic level, the issue 
that we have there is interference.
Now the interesting thing is, if you go
to the microscopic level, and that's what 
you see here, then this interference effect
actually becomes key to solving the
problem, so that is the thing that we use.
Let me now give an example of how such a
logic gate works, that's what you see
here, let take this thing here. This
thing here is a logic and gate, it has
two inputs and one output, and we
designed this thing to do a boolean
operation where we have an output only
in the case when both of the inputs are
on. So we have a two stage process
for that, the first thing that we do 
here is we use interference in this optical
combiner, we make sure that we have a
strong field only when both of the
inputs are on. Then the next stage
that we have here is this micro ring and
this micro ring allows us to make a strong
distinction between the on and the off
level, so that the next gates which
listen to these gates can understand the
signal. The ability to compute data
while it is being transferred and cut out
switch delay, will completely change how
computer architecture is
designed and thought about. When the
computer industry moved from the vacuum
tube to transistor, latency decreased
from in the order of microseconds to
nanoseconds. Photonics promises to reduce
latency orders a magnitude again, in the
order of femtoseconds or less, 1
quadrillionth of a second! This speed factor
alone would radically transform the
computing industry, however, optical
computing as many other pros as well.
Classical computers operate in serial,
with each calculation being performed
one after the other. To scale to more
complex problems requires more
processors, which equates to increased
computing power required and more
complex data management. Optical
computers can operate in parallel to
tackle complex problems through light
reflection, as well as have increased
bandwidth as compared electron based
computers due to the ability to
transport multiple wavelengths of light
at the same time, photons are also
massless meaning that they require much
less power to excite. These factors,
increased parallelism and bandwidth,
translate to extremely scalable systems
which are much more powerful, utilize
less power
and don't come coupled with complex data
management issues. This reduction in data
management also has a major impact on
security, our modern computers have data
travel all over the place: from storage
to different levels of memory to the
cache, then finally read by the CPU which
determines if it can process the data or
has to send it to another computing
device, and then repeats the process all
back again to storage. This exposes a
lot of points in the computer where data
is vulnerable. With optical computers,
since data can be computed while it is 
in motion, translates to increased
security, as less data is exposed. As you
can see, optical computers present many
benefits over classical computers. Coming
up, we'll cover some of the various
optical computing initiatives as well as
how this technology is to be integrated
with current computing systems.
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As discussed in previous videos in this
computing series, data transfer is one of
the largest bottlenecks in terms of
computing performance, however with
optical computing and the ability to
compute data in motion, solves this
problem. Unfortunately with one problem
solved,
creates an other, computing devices will
now end up becoming the bottleneck. To
solve this,
there are various initiatives currently
in both research and development to
push the field of optical computing
devices forward. One of the most widely
known is by a company called, Optalysys.
They are designing an optical
co-processor, referring back to the last
video in this series, this is exactly
what we discussed, new types of chips
that will work within heterogeneous
system architecture. This optical
co-processor will benefit many sectors
and due to the parallelism in photonics,
many of the tasks this co-processor
will excel at are the exact same as
tasks currently offloaded to GPUs. Both
this optical processor and GPUs
working together will 
yield performance boosts like we've
never seen before: Our approach is
completely novel, because we use light
to process data, not electricity. The
Optalysys system connects to and
turbocharges existing computer setups,
whether they are standard desktop
computers or a larger high performance
computing cluster. It essentially
transforms a desktop machine, into an HPC
system, that increases the processing
capabilities of an existing
supercomputer to beyond what current and
even future systems can perform. It does
this by taking on certain mathematical
processes that can be performed faster
in the optical domain. Beyond optical
computation devices, another area of
research and development currently is
memory, more specifically -
optical RAM. While data can be computed
in motion, to access data would still be
a significant bottleneck, unless memory
enters the optical domain as well. In R&D,
through a joint collaboration by various
European nations, optical RAM promises to
be over 30 times faster than SRAM aka
the CPU cache and 1,000 times better
than DRAM. This equates to memory
latencies in the order pico
seconds, unheard of speeds for memory! For
more in-depth information on: memory, GPUs
and heterogeneous system architecture, be
sure to check out the previous videos in
this computing series. Back on topic,
there are many other optical and 
optoelectronic devices in research and
development that we haven't even covered,
with optoelectronic devices mixing both
electron and photon based computation.
For example, transistors that can
switch between both electron and
photon domains and Intel's optical
multiplexers that convert between
optical and electronic signals. The final
topic in optical devices that cover
revolves around silicon photonics,
essentially like fiber optic but on a
smaller scale: The X1 photonic module, and
just as a comparison, this is a 1.2
terabit photonic module and  this is a 1.2
terabit electronic cable. You can see
the difference, and it's more than just
the incredible weight and consumption of
material resources it takes for the
electronic communication,
the thing that's really amazing is that
I can go this 10 centimeters or I can go
a thousand meters, for exactly the same
amount of energy, and that's the
breakthrough from the system level
designer that's so amazing about this
kind of highly integrated very low cost
technology. Silicon photonics, like that
demonstrated by HP can transfer data at
a rate of 1.2 terabytes per second
at a distance up to 100 meters, in fact,
even extending out to 50 kilometers the
transfer rate is still 200 gigabits per
second. For comparison, Thunderbolt 3 taps
out at 10 gigabits and the current fastest
ethernet connections in data centers
at 100 gigabits per second. While at
first this technology will be limited
to the enterprise side of computing in
terms of data centers, we will
immediately begin to see improvements
through increased cloud computing speeds.
In time, as silicon photonics improves, it
will move down to the consumer level and
terabit speeds will be as simple as
plugging in a wire at the back of your
computer. In the grand scope of things,
fiber optic speeds will be slowed down no
longer. From a fiber internet connection
to photonic wiring and then to photonic
computing, computing at the speed of
light, is the long-term goal of this field
computing and will produce massive
performance and efficiency gains. Optical
computing is a field that has been
talked about for quite some time, since
the 1960s, and has produced many advances
in various technologies. However now,
after decades of research and
development, is yielding tangible results
that can accelerate computing
performance. Photonic based computing
will also play a significant role in
quantum computing, due to the particle
wave duality of light. We'll cover this
topic in the next video in this
computing series!
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At this point the video has come to a
conclusion, I'd like to thank you for
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content. This has been Ankur, you've been
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see you again soon!
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