Programming Optical Circuits for Specific Applications and Cost Reduction …

Silicon photonics is an evolving technology that transfers data between computer chips through the use of optical rays that can carry much more data in less time than electrical conductors. The concept involves combining silicon and laser technology into a single chip, a silicon photonic chip. It is an enormously promising area of ​​technology that saw impressive growth last year, with the shipment of more than 3.5 million silicon photonic transceivers. for data centers, with revenues of about $ 364 million. From now until 2026, Global Market Insights expects the silicon photonics market to grow at more than 30% YoY to a value of more than $ 3 billion.

Photonic applications of expanding silicon

Now, in a move that could see the market for silicon photonics grow even further, researchers have developed a new method for building low-power, programmable embedded switching units on a silicon photonics chip. By allowing a generic optical circuit to be manufactured in bulk and then programmed for specific applications, such as LiDAR, the new method could significantly reduce production costs, a major barrier for manufacturers, and allow wider access. “Photonics silicon is capable of integrating advanced optical devices and microelectronic circuits on a single chip, “said Xia Chen, a member of the research team at the University of Southampton. “We expect configurable silicon photonic circuits to greatly expand the scope of applications for silicon photonics while reducing costs, making this technology more useful for consumer applications.”

The wafer scale test being tested by the University of Southampton (left). The prober autonomously and accurately performs optical and electrical device tests at an average speed of less than 30 seconds per device. Image credited to Xia Chen, University of Southampton

Erasable components

The team’s work builds on previous research in which an erasable version of an optical component was developed. This component, known as a grid coupler, was created by implanting germanium ions into silicon. These ions induce damage that alter the refractive index of the silicon in the area where they are implanted. Once altered, heat can be applied to the local area using a laser annealing process that reverses the refractive index and erases the grating coupler.In their own research, the team describe how they applied this germanium ion implantation technique to create erasable waveguides and directional couplers, components that can be used to make reconfigurable circuits and switches. This is the first time that submicron erasable waveguides have been created in silicon. “… we discovered that a carefully designed structure and the use of the correct ion implantation recipe can create a waveguide that carries optical signals with reasonable optical loss,” Chen said.

A wide range of applications

The researchers demonstrated this approach by designing and manufacturing waveguides, directional couplers, and 1 X 4 and 2 X 2 switching circuits. The photonic device of different chips tested before and after laser annealing showed consistent performance. And because the technique involves changing the routing of the photon waveguide through a single operation, no additional energy is used to retain settings when programming. The technology developed by the research team could have a wide range of Applications. These include integrated detection devices for biochemicals and optical transceivers for connections used in high-performance computing.