Versatility and the value of broad protection

Without doubt, photonics is one of the key quantum-enabling technologies. A recent joint European Patent Office (EPO) and Organisation for Economic Co-operation and Development (OECD) report indicates that demand for photonics skills in quantum-related job postings far outpaces other enabling technologies, such as semiconductors, lasers, ultra-high vacuum, and optical tweezers, increasing from 10% of total quantum-related online job postings in 2021-2022 to 14% in 2023-2024.

This is unsurprising given the vast range of applications of photonics within the quantum sector. For example, in quantum computing photonics are utilised for control of qubits in trapped ion or neutral atom quantum computers, the use of photons as qubits in photonic quantum computers, qubit-photon interfaces (QPIs) for connecting quantum processing units together into functioning networks, and many more.

However, the applications are not just limited to quantum computing. Photonics are also used for entangled photon sources for quantum key distribution, and in quantum sensing devices, for example to create optical lattices for cold atoms in quantum atomic clocks or GPS-less quantum navigation devices.

It is also important to note that the applications of photonics extend outside of the quantum sector. One of the main drivers behind the growth in photonics is the rapid growth of artificial intelligence. As the demands of AI continue to increase, copper simply cannot keep up. Therefore, technologies like photonic integrated circuits (PICs) for optical switching and processing are becoming more popular, due to the potential reduction in energy demands and speed.

In view of the wide-ranging applications of photonics, it is important that patent applications be drafted with an appropriate scope, so as to maximise the value of the IP. While the invention may have been originally devised for one specific purpose, it should be considered whether the invention could, either now or in the future, be applied for a different purpose. Research and development priorities often change year-on-year, so the patent specification should bear this in mind and not tie the invention to only one use case or field of use, to ensure that commercially valuable products can be protected in line with changing commercial priorities.

Strategic jurisdictions and the manufacturing reality

Photonics hardware such as PICs come in various forms. For example, devices can be manufactured using more traditional materials such as silicon (Si) and indium phosphide (InP), or newer materials such as thin-film lithium niobate on insulator (LNOI). Each material has trade-offs, but ideally the claims of the patent specification should be as functional and material-agnostic as possible, to maximise scope of protection and avoid work-arounds for competitors.

It is typical practice to have a method of manufacturing claim in a patent specification for a photonics device, however device structure claims are equally, if not more, important. While method of manufacturing claims do automatically protect devices which have been manufactured by a protected method, it can be difficult to prove that a particular method was used to manufacture a device. Accordingly, the safest approach is for the patent specification to include claims to the structure of a device, alongside claims directed to a manufacturing method, even if the inventive concept lies in the manufacturing method. However this is only possible to the extent that the manufacturing method results in a novel device structure.

On the topic of manufacturing, it is also important to consider geographic locations in which manufacture of the device is possible. Due to the complex semiconductor structures in some photonics devices, many photonics companies are ”fab-less”, with manufacture of a particular product only being possible in a small number of territories across the world. As patents are territorial, it is therefore important when deciding upon a geographic strategy for a patent family to consider this geographic manufacturing limitation.

In particular, if patent protection can be obtained in a small number of key manufacturing territories, patent enforcement can become a much simpler process. By preventing manufacture of the product in the first place, the benefits of extending patent coverage to additional end-use jurisdictions can be reduced, potentially saving costs. This approach can also prevent logistically-challenging processes of enforcing patent rights in numerous jurisdictions. Therefore, while it is always important to consider the commercial end-market, protecting your invention in a small number of countries where it is possible to manufacture your product can often better restrict a competitor’s ability to copy your product in this sector.

With this in mind, Taiwan is therefore an important market due to its semiconductor manufacturing capabilities. Conventional patent filing strategies normally file a Patent Cooperation Treaty (PCT) application 12 months after a first filing, where the final decision regarding the geographical scope of patent protection can be made around 30 months from the initial priority filing. However, it is important to note that Taiwan is not a PCT signatory. This means that patents in Taiwan can only be obtained via a direct national filing within 12 months of an initial priority filing. This requires that applicants and patent attorneys are alert to the commercial goals of a patent family at a relatively early stage, to ensure that this important territory is covered.

Distributed manufacturing and secondary infringement

With photonics devices, such as semiconductor-based PICs, one potential way that infringers may attempt to circumvent patent protection is to utilise distributed manufacturing, where portions of a device may be manufactured in one country, and the manufacturing process is completed in another territory. Due to the territorial nature of patents, manufacturers or importers of a portion of a patented product may therefore not directly infringe a patent in any given territory.

To avoid this difficult scenario, patent claims should be drafted broadly, covering only the essential features of the inventive concept, with as few additional features as is reasonably possible. Claims should also be drafted with high granularity, where instead of only including claims directed to a full device, different portions of a device are claimed individually. These good practices can reduce the ease with which distributed manufacturing practices can circumvent patent protection in key territories.

In reality, this approach will not always prevent competitors from avoiding direct infringement of a patent claim. However, in such cases distributed manufacturing techniques can fall under the law on contributory (indirect) infringement. For the UK, this means that when a person provides an essential element for carrying out an invention, but does not necessary directly infringe the claims of the patent in the UK, that person may still be considered to infringe the patent. Importantly, however, this is only the case if said person knows, or it is obvious, that those essential elements provided are intended for putting the invention into effect in the UK.

In the context of distributed manufacturing for photonics, this means that if a person in the UK provides an essential element of a patented photonics device, but not the device in its entirety, they may still infringe the patent, provided the knowledge requirement is met. This can provide much-needed reassurance for patentees. However, this also means that patentees must stay vigilant to contributory infringement, and if appropriate provide appropriate notification of patent rights to potential infringers through permitted communications, bearing in mind the law on unjustified threats.

Conclusion

Photonics has emerged as perhaps the most important enabling technology for current deep-tech trends, such as quantum technologies and AI, and its importance is likely to continue to grow in the coming years. To capture the full value of this importance, patent strategies must look beyond immediate use cases and prioritize broad, manufacturing-aware protection that secures an invention's place in the global supply chain. If utilised correctly, patent protection in this key sector has the potential to provide enormous value and extended commercial advantage for numerous years.