New Programmable Material and PIC Fabrication Method Could Speed Up the Design Process

April 03, 2020 by Luke James

A new innovative fabrication technique for reprogrammable photonic circuits has been developed by researchers at Eindhoven University of Technology.

As we know, our digital society relies on integrated circuits (ICs). In the future, however, these may be unsuitable for emerging technologies and applications such as quantum computing and environmental sensing. 

Photonic integrated circuits (PICs) are the light-based equivalent of ICs that offer lower energy consumption, enhanced performance, and faster operation. 

Now, researchers at the Eindhoven University of Technology in the Netherlands are said to have developed reprogrammable photonic circuits based on a novel programmable material. According to their research–published in Volume 8, Issue 6 of Advanced Optical Materials –this could speed up the rate at which engineers can design and develop working photonic devices.


Challenges Facing Photonic Integrated Circuits

PICs carry signals using visible and infrared light. Therefore, the use of optical materials with adjustable refractive index are essential for reconfigurable PICs because these allow for accurate manipulation of light as it passes through the material, improving performance. 

Current reprogrammable PICs exhibit issues such as high optical signal losses and volatility, both of which affect a material’s ability to maintain its programmed state. Furthermore, current fabrication methods lead to a huge variability between fabricated devices. This causes a limited yield, long delays between the initial conception and ultimate deployment of devices, and an inherent lack of configurability.


Reprogrammable photonics circuits graphic.

A graphical representation of the new approach invented by Eindhoven researchers to develop reprogrammable photonic circuits. Image credited to the Eindhoven University of Technology


How the New Approach Is Said to Improve PICs

According to Oded Raz, an Associate Professor at the Department of Electrical Engineering and the research project’s lead, the new approach could be of “paramount importance” for PICs. This is because it represents the world’s first demonstration of a reconfigurable PIC where the optical material can be programmed, thus allowing light to be accurately manipulated. 

The new method is also said to be able to “significantly improve [the fabrication] yield”, which could represent a major improvement in contrast to existing methods where the yield is relatively low and the time to prototype is relatively high. By placing heaters on a pre-light exposed device, the user could also program a PIC device as desired and reset it to a state for reprogramming, thus making it reusable and sustainable.


Furthering the Development of Photonic Devices 

Crucially—if viable—this approach will allow users to easily program PIC functionality and concurrently correct for small errors in the fabrication process.

The research team is therefore hopeful that their new approach could facilitate further investigations on reconfigurable PICs. And because the time to prototype is much shorter and accurate with their method, the programmable material might speed up the rate at which engineers could develop working photonic devices. And as the method is refined, Raz believes that the time to prototype will continue to decrease.

It is important to keep in mind that these are still early days. Although the research team is clearly hopeful for its new programmable material and fabrication technique, lots of testing and experimentation will be needed before its significance can be accurately assessed.