“One-Way” Electronic Devices

Waves — whether they are light waves, sound waves, or any other kind — travel in the same manner in forward and reverse directions. This is known as the principle of reciprocity. If waves could be routed in one direction only — breaking reciprocity — many applications could be transformed by enabling “one-way” components such as circulators and isolators that enable two-way communication, which could double the data capacity of today's wireless networks. These components are essential to quantum computers that read a qubit without disturbing it. They are also critical to radar systems in self-driving cars or those used by the military.