In an effort to help meet the challenge of providing Canada's remote and underserved communities with high-speed internet, the National Research Council of Canada's (NRC) High-throughput and Secure Networks (HTSN) Challenge program is supporting a project that aims to improve existing wireless and wireline infrastructure in a cost-effective way.
The project focuses on optical access networks. These networks are the part of a telecommunications system that connects end users with their local service providers. One of the goals is to increase the rate at which data is transferred, also known as the 'throughput'. The project also aims to reduce the power consumption and simplify the design, deployment and operation of these networks.
To do all that without creating new networks requires creative thinking and out-of-the-box solutions. NRC researchers have come up with an elegant approach: creating a new type of transceiver using existing technologies. Transceivers convert electrical signals to optical (light) signals and vice versa.
At the heart of this new technology is an NRC invention: the quantum dot optical frequency comb. A frequency comb is a special kind of laser that emits light at multiple, precise wavelengths spaced like the teeth of a comb. While standard lasers generally emit light of a single wavelength (or colour), the NRC's comb can generate dozens of wavelengths at once. "That means you don't need different transceivers for each wavelength, so that saves providers a lot of money," says Dr. Jiaren Liu from the NRC's Quantum and Nanotechnologies Research Centre. "The NRC's lasers also have very low phase and intensity noises, which are important for coherent modulation and detection."
The technical complexity of miniaturized comb sources makes application design very difficult. That's why it was critical to bring together a multi-disciplinary team of researchers to solve the problem. This collaborative project draws on expertise and talent from the NRC, McGill University and FONEX Data Systems Inc., a Canadian enterprise. While we provide expertise in semiconductor technologies and optical sources, McGill offers testing facilities and students who conduct analytics, simulations, experiments, and validation and characterization of laser sources. FONEX's strengths include component characterization and design, and market savvy.
A streamlined solution
To meet the needs of providers, the partners are exploring the development of transceivers using the NRC's quantum dot laser technology and FONEX's quasi-coherent receivers. Ideally, the solution would collapse 32 transceivers into one.
"That's the real value proposition," says FONEX's Chief Technology Officer Pasquale Ricciardi. "Rather than having separate lasers for discrete applications, you now have one laser with different combs to accommodate multiple laser sources and frequencies." He points out that the NRC's technology can be used in one portion of the system, while FONEX and McGill's new technology based on their tunable laser can round out the architecture.
At a system level, combining the NRC's comb source with FONEX's tunable laser could achieve the speed and services that customers need. By blending their talents, researchers can resolve technical challenges that the new concept may present. For service providers, the potential net result is a more efficient and cost-effective means of delivering reliable and secure internet connectivity through optical network architectures and technologies, even in remote and underserved communities.
"Projects like this are very important to industry because working with academics and other experts helps reduce our risk when trying to innovate," says Ricciardi. FONEX is building a prototype of the hybrid transceiver and working with McGill and the NRC to adapt it for commercialization. So far, the research teams have tested cost-effective and marketable transceiver architectures and corresponding digital signal processing algorithms.
Dr. Lawrence Chen, a professor of electrical and computer engineering at McGill, reports that his team has developed a system test bed to validate some of the components developed by FONEX and the NRC. He adds that FONEX contributes to the partnership by identifying new applications for comb structures. "Working with FONEX has helped us move it from a conventional academic exercise to something that could be commercialized."
A new twist on innovation
This is an example of innovation by evolution. "We are simply collapsing multiple transceivers at the network head end into a single element," adds Ricciardi. The end point becomes scalable and can operate across the entire customer base. This allows providers to use their existing infrastructure without investing in new assets.
"For the country, it's important to have an organization like the NRC that innovates and helps Canadian companies do the same," he concludes.
This research was supported by grants and contributions awarded through the Collaborative Science, Technology and Innovation Program administered by the NRC's National Program Office.