By Dr. Michael Lebby, CEO, Lightwave Logic
What is the internet? To some, it’s simply a utility—a place to shop, learn, teach, talk, see, communicate. To others, it can be life saving for medical, environmental, and ecological uses. It is quite incredible what we as a society can do with the internet today. Just imagine what we could do with the internet in the future. A question that will be at the back of people’s minds is: how can we make sure our quality of life will be and will continue to be enriched? Enriching means an internet that is better performing, and somehow, we have to scale what it is today to something better tomorrow.
Let’s take a very simple example that most of us have experienced over the past year or so: remote working, schooling, teaching, and using video platforms. Our lives have changed for sure, but at times, the internet has been a headache—why? Simply put, some of us don’t have enough bandwidth of data entering and/or leaving our home. This has meant that we have had to turn our cameras off to save data (even recently, I was on a video call and I needed to do this to maintain the communication link)! This is not an easy problem to solve—but if we want to enrich our lives, we definitely need some radical innovations for the internet, and one exciting candidate is the use of electro-optical polymers (or simply optical polymers).
What Is the Internet?
The internet is essentially a network of glass-based fiber optic cables that link huge electronic switches that route traffic to their destination. Using a road analogy, it’s like the interstate, state, and local city roadway systems across the country. Many people have a road that goes right up to their front door; this is essentially the equivalent to your connection to the internet that connects with your home. The connection could be cable, wireless, or a plain old telephone (POT). Nevertheless, as traffic leaves your home—it could be via an email which has been directed to another state—it most likely will get routed via fiber optic cables and electronic switches called data centers, so that it ends up at the correct destination. At some point, the email may go via city roads, then state roads, even perhaps the interstate highway, especially if the email is going across the country.
In today’s commercial and manufacturing environment, companies require higher data rates, allowing easier access to higher-quality data flow, which in turn permits a higher quality of information—and more efficient product development.
Using the roadway analogy again, one way to think about the internet and how it could enrich our lives with radical innovation is to think about speed.
For most of us who drive motor vehicles on public roads, our speed limits are perhaps around 50-75MPH depending on state and local laws. How much has the speed of these roads changed in the last couple of decades? Very little. It would seem to the casual observer that we have reached a saturation point even though cars have improved in design and performance. Then what have we done to the road system to carry more traffic? We clearly can’t go faster, presumably due to safety issues, so we have added more traffic lanes. In major cities such as Los Angeles, Chicago, and New York, roads with 4, 5, or 6 lanes in each direction are not uncommon. Unfortunately, we still have traffic jams, and the road system clogs.
If we now think about our internet as an equivalent roadway system, we’ve sort of created the same thing as extra traffic lanes—we’ve added optical channels to increase data flow. We’ve used a technical innovation developed in the 1990s called wavelength division multiplexing (WDM). This allows for many optical channels to run at different wavelengths down the same fiber, and subsequently, this allows the internet to carry more traffic. In fact, in optical network architectures, we’ve done more—we’ve increased the symbol rate of each digital signal so that more information can be carried in a digital data cycle. Instead of a simple castellated square wave of 1s and 0s (think of a castle wall profile where a laser sending light down the fiber is a 1, and a laser blocked by a modulator is a 0), we now have created in the optical signal complex staircases and constellations that indeed allow more data per digital data cycle. So, what does this look like from a freeway road perspective? It’s like stacking cars on top of each other, moving down the freeway at the same speed, let’s say 60MPH! In the industry, it’s called “more information per bit”—more information per optical digital bit or digital data cycle. Can you imagine 4 or 5 cars stacked on top of each other going down the freeway? It’s absurd, however, this is effectively what our commercial optical network industry has implemented in order to get more information faster through the fiber optic pipes of the network—or the internet.
The question is: why did the commercial internet industry do that? Simply put, it’s because the optical modulator devices on the internet are limited in speed. They can’t go faster in freeway terms than, say, 75MPH—a bit like cars not being allowed to speed. Optical modulator devices really have not progressed in speed (measured by their device electro-optical bandwidth) much more than ~30GHz over the past couple of decades.
The internet industry is acutely aware of this issue and focused on how to better encode data with more information per bit to effectively increase data rates across the internet. It did this as it was easier to design complex, power-hungry electronics than to get optical modulator devices to operate faster.
While this innovation has worked for the past decade or so, it is quickly running out of steam. Today, the demands for higher data rates and bandwidth for the internet are forcing the internet architects and optical network planners to re-think their strategy. They are being pushed into figuring out how to increase the optical modulator device speed as opposed to encoding more complicated schemes to increase the information per bit. This occurs because the more complex the encoding, the more electronics are needed and the higher the power consumption, as electronic-integrated circuits (ICs) consume lots of power. Higher power consumption is something that they desperately want to avoid. Clearly, a better mousetrap called an optical modulator device is a critical need for the internet both today and in the future.
How Do We Scale the Internet with Better Modulators?
The key metrics in performance for optical modulator devices that are important to architects of the internet today and over the next decade are: (a) optical modulator device speed measured in bandwidth, (b) optical modulator device power consumption, (c) optical modulator device footprint size, and (d) optical modulator compatibility for photonics integration.
Taking the optical modulator device as a critical device that both scales and enables a more competitive internet, then the following scaling metrics at least need to be addressed:
- High volume—must be able to scale in foundries and large fabrication plants
- Low cost—material must be able to scale in cost, with no supply issues
- High speed—optical modulator devices that are at least 3X faster than current semiconductor incumbent technologies
- Low power—optical modulator devices that have an impact of at least 10X reduction of power for the internet architecture
- Ultra-small size and footprint—size is an issue for the internet, and optical engines that contain modulators can alleviate this issue
- Integration onto a Photonic integrated circuit (PIC) platform—following the IC industry, more functionality on a chip creates PICs that are more efficient and practical.
Today, optical modulators are used everywhere on the internet; however, they are semiconductor based, using materials such as lithium niobate, indium phosphide, and silicon. With all these materials, the optical modulator design has reached a saturation point in performance, which means it’s time to look at a new technology platform.
Stage entry: Polymer optical modulators. Polymer optical modulators are devices that switch light over 3X faster than existing optical semiconductor devices. Furthermore, they relieve the architecture of the internet by taking away the chains of limited optical speeds. This allows the internet to keep competitive by allowing speed to continue growing. Coming back to the road analogy, this is like increasing the speed of the motor car as you drive on a road, and not just a little bit, but significantly.
How Can Polymers Affect the Internet?
Optical modulator devices made from electro-optic polymers are supported in general by Mother Nature. Their inherent material properties allow them to achieve performance specifications significantly better than their semiconductor brethren.
Electro-optic polymers have several interesting attributes in addition to speed—they help lower the power consumption of the optical modulators, which in turn helps address the ever-increasing power issue that the big data-center-type facilities encounter as part of the internet architecture.
They can also have a very small footprint or size, which is very important for crowding lots of optical polymer modulators into packages, and lastly, optical polymer modulators have excellent compatibility for photonics integration. The optical polymer modulator together with either silicon or indium phosphide semiconductor PIC platforms as a hybrid PIC platform is poised well to enable scaling for performance for the internet. We call this a “hybrid PIC” and we see the hybrid PIC becoming an engine of growth by increasing data rates via the optical polymer modulator(s), lowering power consumption via the optical polymer modulator, and squeezing lots of photonic devices onto a semiconductor platform through integration.
Will Optical Polymer Modulators Be Reliable for the Internet Once They Are Scaled?
Optical polymer modulators are an organic electro-optic material that switches light fast. Both the switching of light and the optical polymer material are two characteristics that are common in today’s consumer world. For example, we see optical switching every day with our TV and display screens that use LCDs. LCDs switch light, albeit very slowly. So, LCD technologies have given way to an optical polymer technology that we see every day called organic light emitting diodes (OLEDs). Some of us have those beautiful OLED TVs and displays in our homes today. These are all optical polymer based. If you combine the functions of super-fast optical switching with optical polymers, you end up with electro-optic polymer materials that switch light very fast. This is exactly what is needed to switch optical data super fast in fiber communications and the internet.
While LCDs have been replaced in part with OLEDs, the success of optical polymers in OLEDs have been incredible over the past decade. Many OLED displays have replaced LCD displays, and the reliability of the new displays is high quality—in fact, so high that we never question quality or reliability these days. While electro-optic polymers do not emit red/green/blue light emissions, they are organic, polymeric, and switch light as opposed to generating light. Although they are created from different chemical compositions, they also can provide long lifetimes, stability, and high reliability when used in products.
Given the natural advantages of electro-polymer material, the companies that source the organic polymer compositions for optical modulator device designs will have a big say in how this innovation of technology is integrated and implemented into market applications for at least the internet. Optical polymers are the sunrise technology for the internet, while semiconductor technologies for optical modulators are seeing the sun set on their usefulness.
How Will the Technology Be Implemented?
Optical polymer modulator technology platforms are now based on the use of large, complementary metal-oxide-semiconductor (CMOS) silicon foundries. These are fabrication plants that focus on silicon semiconductors and traditionally have set up their recipes, or what the industry calls a process development kit (PDK), for integrated circuits, or ICs. Over the past few years, many silicon foundries have been looking at increasing their wafer throughput by servicing silicon photonics solutions. It is these foundries that are the catalyst for volume scale when optical polymers are added to silicon photonics. Transporting the standard semiconductor fabrication techniques to a large foundry in terms of a PDK is relatively straightforward, as the processes are amenable and compatible.
To have optical polymer modulators ubiquitous across the industry, key milestones are being achieved at record pace: advanced and mature electro-optic polymers, simple and standard fabrication in large-scale volume, and packaged modulator device implementation into commercial applications. The optical polymer industry for fiber communications is growing quickly, and with the correct positioning for scale, volume, and performance, electro-optic polymers are poised very well to enable optical network system businesses to be much more competitive.
What This All Means
Scaling the internet through drastic innovation really boils down to the design of optical polymer modulators that have inherently increased the speed of the optics, lowered power consumption, are tiny, and allow for creative integration onto hybrid PICs. This clearly is the radical innovative engine of change for the internet. The future for the internet never has been so exciting!
Dr. Michael Lebby has served as Lightwave Logic’s CEO since May 1, 2017, and as a director since August 26, 2015. From June 2013 to 2015, Dr. Lebby served as President and CEO of OneChip Photonics, Inc., a leading provider of low-cost, small-footprint, high-performance indium phosphide (InP)-based photonic integrated circuits (PICs) and PIC-based optical sub-assemblies (OSAs) for the data center market. Dr. Lebby holds a Doctor of Engineering, a Ph.D., an MBA, and a bachelor’s degree, all from the University of Bradford, United Kingdom. Dr. Lebby has well over 200 issued utility patents with the USPTO.
 The digital signals that are used to convey traffic through the fiber optic cables on the internet are produced by lasers and modulators that send the light to generate the 1s and 0s. The laser produces the light, and the modulator switches the light to create the 1 and 0. This is a bit like blinking your eyes very fast or chopping a light signal by waving your hand in front of a flashlight! When your eyes are open and the route is clear, light can travel, so it’s a 1, and when you blink, and the route is blocked, light can’t travel, so it’s a 0. This is called encoding the signal, and encoded light carries our information across the internet as we access websites and communicate.
 Optical modulator devices are normally measured in terms of their electro-optical bandwidth. Today, incumbent semiconductor optical modulator devices operate with electro-optical bandwidths of 25-35GHz, and these figures have not significantly changed over the past decade.
 PICs are semiconductor chips that contain many photonic devices, including optical polymer modulators, that are integrated together on the same chip.
 PDK is a Process Development Kit, which is sort of like a food recipe for big silicon fabrication plants. For example, when fabricating silicon wafers into integrated circuits, it is the PDK that engineers use in the fabrication plants.