The development of photonic integrated circuits (PICs) is an expensive and time-consuming process. Nanofabrication facilities cost millions of dollars to construct and are well beyond the reach of many colleges, universities, and research labs. For those who can access a nanofabrication facility, at least a day must be reserved for the exacting and time-consuming lithographic process used to make these microchips. On top of that, if an error is made in design, or if the chip does not work properly for some other reason, the faulty circuit must be discarded, the design adjusted, and a new chip fabricated. This often results in days or even weeks spent in the cleanroom. Researchers led by the University of Washington (UW) have developed a method to produce photonic integrated circuits almost anywhere. The technique enables PICs to be written, erased, and modified by a laser writer into a thin film of phase-change material, similar to what is used for recordable CDs and DVDs. The process allows PICs to be constructed and reconfigured in a fraction of the time it would take at a nanofabrication lab. “It’s a matter of minutes versus a full, day-long process,” said UW graduate student Changming Wu, lead author of the paper. The researchers demonstrated the versatility of the printer by creating an optical interconnect fabric for reconfigurable networking, a photonic crossbar array for optical computing, and a tunable optical filter for optical signal processing. A research team led by Mo Li, physics professor at the University of Washington, has developed a way to print and reconfigure photonic integrated circuits using a speedy, low-cost device about the size of a conventional desktop laser printer. Courtesy of Haoquin Deng/University of Washington Electrical and Computer Engineering. With photonics technologies on the horizon, students and workers need to be trained and gain hands-on experience with photonic integrated circuits, said Mo Li, physics professor at UW and senior author on the paper. “This new technology addresses that problem. Using our method, photonic circuits that previously had to be fabricated in expensive and hard-to-access facilities now can be printed and reconfigured in labs, classrooms, and even garage workshops, by a speedy, low-cost device about the size of a conventional desktop laser printer.” For researchers, this advance will enable a much quicker turnaround time for prototyping and testing out a new idea before booking valuable time in a nanofabrication facility. And for industrial applications, one of the advantages of this method for producing PICs is reconfigurability. For example, companies could potentially use this technology to create reconfigurable optical connections in data centers, especially in systems that support artificial intelligence and machine learning, which would lead to cost savings and production efficiencies. While the printer has demonstrated its versatility, it is still in its early stages of development. However, Li has filed a provisional patent application, and he has plans in progress to build a desktop laser writer for photonic integrated circuits. The team will be seeking ways to optimize its performance as they build a prototype. They will also be working to reduce optical loss in the phase-change material through further research in materials science and laser writing techniques. This will enable the printer to produce even more detailed and sophisticated circuits than is currently possible. Li expects that the printer could be sold at an affordable price and distributed widely to research labs and educational institutions around the world. He is also engaging with industry leaders to promote possible applications of this new technology in programmable photonic chips and reconfigurable optical networks. The research was published in Science Advances (www.doi.org/10.1126/sciadv.adk1361).