For the first time in the field of photonics, researchers created diodes made of light that can be used to make circuits.
According to reports, researchers from the National Physical Laboratory in the United Kingdom have achieved a ground-breaking feat by creating diodes made of light. The team asserted that their light diodes could be used in the development of miniaturized photonic circuits.
In the study published in the journal Optica, the researchers led by Dr. Pascal Del’Haye explained in detail how they made an optical version of a diode that is capable of transmitting light in one direction only and can be integrated into microphotonic circuits.
For years, small-scale integration has been a major hurdle in photonics because current optical diodes need large magnets.
“A challenge for integrated photonic circuits is the realization of nonreciprocal elements like isolators and circulators. Most optical isolators and circulators are based on the magneto-optic Faraday effect, which requires the integration of (electro)magnets,” the researchers wrote in their paper.
Dr. Del’Haye and his team’s work has reportedly overcome this limitation by utilizing light stored in tiny chip-based glass rings to develop a diode.
Creating Diodes Made of Light
Diodes are semiconductor devices that typically serve as one-way switches for electric current. They enable current to flow smoothly in one direction while restricting it from flowing in the opposite direction. Nearly every electronic circuit today uses diodes to manage the flow of current.
For the researchers to create diodes made of light, they used a technique that sends lots of light into a microresonator, or a glass ring on a silicon chip about the size of a human hair. By harnessing the circulating optical power in the process, the team was able to produce the diode effect.
“To create the optical diodes we used microrings that can store extremely large amounts of light. This meant that, even though we were only sending small amounts of light into these glass rings, the circulating power was comparable to the light generated by the flood lights in a whole football stadium – but confined into a device smaller than a human hair. The light intensities enable the formation of a diode via a light-with-light interaction called the Kerr effect,” Dr. Jonathan Silver, a higher research scientist at NPL, explained.
During their experiment, the researchers were able to demonstrate how the electromagnetic field of clockwise circulating light in the glass rings successfully blocked the counterclockwise circulating light.
“These diodes will, for the first time, open the door to cheap and efficient optical diodes on microphotonic chips, and will pave the way for novel types of integrated photonic circuits which could be used for optical computing,” Dr. Del’haye went on to say.
“They could also have significant impact on future optical telecommunication systems, for more efficient use of telecom networks.”
On the other hand, Leonardo Del Bino, one of the researchers, was also quoted as saying:
“A remarkable property of this novel diode is that the performance improves if the forward propagating light field is increased. This is very important, for example, when using the diode to protect chip-integrated laser diodes from back reflections.”
Aside from creating diodes made of light, the researchers’ study could also pave the way for new types of optical rotation sensors and optical memories to be developed.