Conversation with Giorgio Grasso, founding partner of Subphoton and one of the world’s leading experts in photonics: he has 60 international patents to his credit.

“Subphoton opens up a world of great interest because everyone talks about the Internet, but no one thinks about the fact that this data travels over huge cables.”

Let’s start with his route.

“I started working at Pirelli Photonics in 1972 in the specific field of fibre optics. In ’85 we started with the development of erbium fibre optic amplifiers. It was basic research that gradually became applied research, then technological development and then a product. In 1992 we realised the world’s first installation of an optically amplified system, in America, 3500 km between South Lake City and Chicago. And it was there that the real adventure began: the application of photonics in the field of telecommunications.  Before the optical amplifier, in fact, there were optical fibres, which had their own potential, but with the problem that light, passing through the fibre, lost intensity. Consequently, every 30 to 40 km, it was necessary to transform the light into electric, amplify it electrically and pass it back into optical. This was the task entrusted to the optical regenerators. “

Which are being put on hold thanks to a new technology.

“Exactly. The innovation, at the time, was to make an optical amplifier that did not need to pass in electrically, but which amplified light directly. This gave great advantages, especially in terms of capacity: fibre can transmit a huge amount of information, but if you use an electronic system, there is a limit in terms of transmission speed and in terms of the number of wavelengths that can be transmitted. A limit due to the fact that there is a very large optical band in the fibre that can transmit as many wavelengths. Each wavelength has its own transmitting capacity, but with the electronic regenerator it is only possible to amplify one wavelength and only at a certain speed, because the electronics are calibrated to a speed. The optical amplifier, on the other hand, allows simultaneous amplification of all wavelengths that can travel in the fibre at any speed. The optical amplifier, on the other hand, allows simultaneous amplification of all wavelengths that can travel in the fibre at any speed.

More efficient and more economical.

“Indeed. The disruptive element in this industry is related to the lower cost of the optical amplifier compared to the regenerator: having an amplifier that cost less and had the capacity of 100-200 generators meant that the cost of transmission was drastically lowered. And, last but not least, the Internet was born at that time, which relied on being able to transmit data from one place to another. The introduction of the optical amplifier made it possible to develop it cheaply, otherwise its diffusion would have been impossible, so we can say that this innovation came at the right time. Many times, in fact, innovation arrives either early when the time is not yet ripe or a little late, whereas this one arrived at exactly the right time, when the need for transmission had grown because of the internet.

This provided an important impetus for photonics. And for his career path.

Yes, at that time there was a real boom in photonics, and by the end of the 1990s Pirelli had become the world leader in this technology. Cisco, which is still the American company that is the queen of the Internet, bought this unit from Pirelli for what at the time was a record sum, about $6 billion. I went to Cisco, where I stayed for about two years and then returned to Pirelli because I was interested in developing new technologies. I started to delve into the subject of integrated optics, which I then continued at the Milan Politecnico. The ideas were very interesting, but the problem was that at the Politecnico, as in all Italian universities, there is a lot of research but never enough in-depth study of industrial application. So, with some former colleagues we decided to create some start-ups to overcome this gap. Two of them are now supported by LIFTT. ”

Can you tell us about these start-ups?

“Subphoton opens up a world of great interest because everyone talks about the internet, but no one thinks about the fact that this data travels on huge cables. The start-up operates in the field of innovative optical amplifiers and in particular optical amplifiers for submarine applications. Submarine cables transmit information over very long distances and are the backbone of the world wide web. The big hyperscalers, i.e. Google, Facebook, Amazon and Microsoft, have servers scattered around the world connected to each other and to customers via submarine cables carrying an enormity of data. The need is to be able to respond very quickly and in fact the servers are connected directly by these submarine cables to reduce latency, i.e. the response delay time between one and the other. At the heart of these connections are the optical amplifiers. The goal, spasmodic and imperative for all hyperscalers, is to increase capacity while reducing costs. Supphoton is studying solutions that go exactly in this direction, all with a simultaneous reduction in consumption, because another important theme is Green telecommunication. “The big hyperscalers, i.e. Google, Facebook, Amazon and Microsoft, have servers scattered around the world connected to each other and to customers via submarine cables carrying an enormity of data.

And CareGlance?

“CareGlance uses photonics to give a three-dimensional image to a small object. In particular, the most widespread application is in ophthalmology, i.e. for viewing the cornea and checking for damage, an analysis that is usually carried out in hospitals, but using large, fixed machines. Moreover, this examination is time-consuming and creates a problem related to the movement of the eye: if the eye moves, in fact, the measurement fails, and the examination has to be repeated. Our goal is to create a miniaturised gun-like object that allows the measurement to be taken quickly, so that both hand and eye remain still, avoiding the use of a large instrument. To do this, we developed a tunable laser: the measurement is done using a laser that makes what is called a ‘wavelength sweep’, i.e. it passes through different wavelengths, and the heart of the object is the speed at which it moves this wavelength. With CareGlance we have found this technology that allows this ‘sweep’ to be done taking, instead of hundreds of microseconds, hundreds of picoseconds, i.e. 100 times less. This results in an important acceleration of the measurement. And this is CareGlance’s mission: to develop this technology, industrialize it and make it a product to bring to market. “

But applications are not limited to the ophthalmic field.

“No, on the contrary, the aspect of the industrial application of the technology has also emerged, stemming from the fact that its core allows small objects to be seen three-dimensionally quickly. I am thinking, for example, of welding in the automotive field, where there is an application with a company in the sector that makes it possible to go and see the quality of welds in real time, or, in the medical field, vision in non-invasive surgery. In this field today you use a two-dimensional camera whereas nowadays, thanks to this technology, you can see three-dimensionally. And being fast you can do it in real time. So, in addition to the initial ophthalmic application, there are also other possibilities that we are studying.”History of submarine cabling

‘Submarine links,‘ Giorgio Grasso recalls, ‘started out as telephone links.  In 1956 the first submarine telephone cable was laid between America New York and England. Before 1956, the only thing that existed were telegraph cables. Between England and America there was no other possibility of talking to each other, for example, because there were only telegraph cables. And anyway, even with the 1956 cable, a maximum of 56 telephone calls were transmitted. Telecommunications operators continued to develop just as the number of phone calls continued to grow, which meant that the cost of the phone call was reduced to zero. With the arrival of the internet, telephoning now costs nothing in America. This is the heart of the internet but if there were no undersea cables there would be no internet. “

The first submarine cable was destined for telegraphy, the internet of the time, the ‘great achievement of human genius that cancelled distances‘ according to the newspapers of the time, and was laid in the English Channel, between Dover and Calais, in 1850. The cable remained operational for only a few days, after which it was possibly interrupted by a fisherman’s anchor. It was soon realised that the cable needed to be strengthened and armoured to protect it from the dangers caused by shipping and sea animals. In 1852 the first direct line Paris-London was established, then England-Ireland and, in 1853, the England-Holland line. In Italy, the first submarine cables began to be laid in 1854 between Sardinia, Corsica, La Spezia and Algeria, and in the Sicilian Channel, followed by the first transoceanic connections in 1858 with the first cable laid by two ships between Newfoundland and Ireland. This progress was made possible thanks to a particular material, Malaysian gutta-percha, which made it possible to preserve the cables from the pitfalls and wear and tear of the sea depths and to extend a land telegraph network through the water, which in just a few years counted over seventy thousand miles in the Old and New Worlds. ”

It is precisely from the history of these cables, and the continuous refinements that have taken place over the decades to obviate the risks associated with their physical dislocation and to increase their capacity, that we learn how this methodology, in addition to its advantages, also presents inherent risks, as well as geopolitical implications that are by no means secondary: the point to ponder is that the ever-increasing need for bandwidth is satisfied almost exclusively by submarine cables, and that there is ample room for improvement to enhance their efficiency and safety.