Q: We have been hearing about LiFi as a disruptive technology for sometime now, has the level of adoption matched your predictions and hopes?
A: It has always been clear that LiFi is a disruptive technology, but for that to happen it will take some time. There are already many people, worldwide, that have recognised the opportunities of this technology and it is all going in the right direction. I predict that we will see this technology introduced to the market in three to five years, on a large scale.

Q: How important is it for LiFi to gain traction during this phase of wide scale LED upgrading in the lighting sector?
A: I see 3 major industries for LiFi adoption; lighting, security and wireless communication. The business model for LEDs in the lighting industry has been shaken up significantly. The lifetime of a light is now, often, longer than a car.

Much like the transition from analogue to digital photography, the LED lighting industry must add new features and services beyond illumination. A light is now an electronic device, which can integrate motion sensors, cameras, photo-detectors, or LiFi, creating an electronic gadget, an “iLight” if you will.

Consider that the mobile telephone 20 years ago was a very different device, now with the advent of smart phones, calls are just one of many phone-based applications. In 20 years from now the illumination will be just one of many features of LEDs, with the majority designed to enable smart environments.

Within wireless communication there are two main trends; the emerging Internet of Things and the spectrum crunch. The wireless communications industry has spent billions on radio, making more difficult for them to adopt light communication (LiFi). However, LiFi will likely be pulled into the wireless communication service provision; I expect to see ISPs offering both LiFi and WiFi in the future.

Q: Do you see LiFi and WiFi as in competition with each other in any sense?
A: The 2 technologies can work together, and each technology will suit certain situations better than the other. For example, if you have your phone in your pocket or where there is no light, WiFi is the better technology, whereas in any situation where the sensor has access to LiFi it will be orders of magnitude better in terms of the signal to noise ratio and data rates.

It makes sense to leverage those advantages of light-based data transfer when light is available. We can achieve a seamless transition from radio to light data systems, and the great advantage is that neither technology interferes with the other. One of the major issues with the radio domain is that signals often interfere with each other, especially in the industrial, scientific and medical (ISM) band with WiFi.

Q: Is it those scenarios where WiFi currently provides sufficient data transfer but LiFi can offer advantages, do you see this change happening?
A: We are able to leverage the small optical atto-cell, repeating the spectrum many times. In a boardroom, for example, where you have 10 LEDs providing illumination you could have 10 times the spectrum that one light provides. This provides significant improvement in area spectral efficiency, which is data rate per square meter per Hertz.

Many company headquarters do not use WiFi because of the potential “leakage” of the signal outside of the room or building creating a security threat, whereas LiFi leakage can be controlled much more easily, by simply containing the light. The security aspect of LiFi is phenomenal, in fact pureLiFiLtd. has recently been shortlisted as one of the top four cyber-security companies in the UK.

Q: We are beginning to see multi-function LEDs enter the market, such as the sensors in LEDs by Enlighted. Do you see LiFi establishing itself in niche areas initially, and do you see its coexistence with sensors and other LED functions?
A: We do see these niche areas as early adopters, before LiFi establishes itself in broader markets. As the level of adoption begins to scale the cost of LiFi will tumble, eventually you will have LiFi in every smart phone and light bulb in the world, hopefully.

I really appreciate developments, such as LED-based sensors as they bring about the age of the multi-function light bulb. Similar to the sensor-based technology coming into the LED market now, we expect to also see the widespread addition of data transfer in the next two to five years.

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Q: As we get closer to adoption, people will ask more about the limitations of LiFi, line of sight gets mentioned a lot in discussions I’ve seen. How would you assess the limitations of the technology?
A: Line of sight limitation is one of the great misconceptions of LiFi. If, for example, a smart phone was held under a table without direct line of sight to the LiFi LED on the ceiling, the light reflected off other surfaces, along with our modulation, would still allow higher levels of data transfer than standard WiFi.

We have created a LiFi communication receiver that can detect a single photon, a single photon avalanche diode (SPAD), and with this device we can achieve sensitivity that is comparable with a radio antenna.

In practical terms, we have been working with the gas industry on well maintenance. Certain parameters, such as temperature and pressure, need to be monitored within gas piping. Every six months production is stopped for maintenance and a cable is used to check the condition of well and pipes.

The maintenance, and consequent loss of production, can cost hundreds of thousands of dollars. A variety of technologies from radio to ultra-sound have tried and failed to provide information safely from the base of the well. With LiFi we have demonstrated in computer simulations that it is possible to transmit information from the bottom of the gas pipe using a single LED to transmit data 4km to our single photon avalanche diode on the surface, without the danger of explosions from the electro-magnetic elements you would encounter with radio.

Q: Considering the potential for single photon sensitivity, how secure is data, would interception be possible on the small amounts of light seen between shutters/blinds or under a door, for example?
A: While tens of photons are sufficient, they must hit the target detector exactly. So, either people need to be lying at the doorsteps, or need to use specialised equipment. If they go done this avenue, the might as well better use directional microphones to record the voices direct.

If we were to interview you again in three to five years from now, what would be the key points of that discussion and your major focus at that stage?
In three to five years we would have seen the deployment of LiFi for specific applications, our major focus would be convincing other industries of the benefits of LiFi for their applications.

Take the National Health Service and our aging population here in the UK. I foresee wearable devices with an integrated micro-LED, in an earring for example, that could measure blood pressure, temperature, even the composition of your blood. This data can then be transferred to the sensors in smart LEDs allowing patients to be monitored 24/7.

This technology may also be developed to allow more patients to leave hospital, where the same process maybe used in their homes and would alert their GP automatically with health information. LiFi can play a huge role within healthcare, providing comprehensive health monitoring benefits, increasing patient comfort, cost savings and easing pressure on hospitals, among other things.

One interesting development came from taking solar cells, which convert photons into energy. We have managed to convert solar cells into data detectors as well as energy harvesters; using an off-the-shelf solar cell we have managed to achieve data rates of 15 megabit per second, the highest ever shown.

Imagine if you combine that with the Internet of Things, where energy provision is one of the major limitations, such a solar cell will be able to receive data as well as providing power to the device, enabling the Internet of Things or smart environment.

Data transfer would also be possible over great distances, in the Scottish Highlands for example, where fibre-optic cable is not widely available, solar cells would provide power and a long-range laser could be used to send data to remote locations, and one would have no issues with hitting the target even in strong winds given the size of a solar cell. This is another patented technology we have developed at the LiFi R&D centre, which we are now commercialising.