According to reports, a chip-based device with an area of only 1 square millimeter has the potential to generate quantum random numbers at gigabytes per second (Gb/s) at the lowest power level. Micro devices implemented by silicon photonics can stand alone in devices such as laptops and smartphones or be built into devices for real-time data encryption.
Researchers at the University of Bristol in the United Kingdom showed a random number generator that randomly emits photons based on the diode laser pointer. Since the photon emission from the laser is essentially random, it is impossible to predict the amount that will be produced. Other desired optical components of the Quantum Random Number Generator (QRNG) are integrated on a silicon (SOI) chip on a millimeter-sized insulating substrate.
Researchers have developed chip-based devices that are only 1 square millimeter in size and produce quantum random numbers at Gb/s. As shown below, this device on the right side of a penny coin includes all the optical components of the random number generator. The device uses an interferometer to convert the emitted photons into optical power. A miniature photodetector integrated into the chip detects the optical power and converts it into a voltage that produces a random number.
Researchers say that only a small number of photons can actually reach the photodetector, and most of the photons are lost inside the chip. To mitigate this effect, the researchers optimized the parameters and designed low-noise electronics to detect optical signals inside the chip.
For testing purposes, the researchers used wafer foundry semiconductor technology to fabricate random number generator chips and used them to generate random numbers after obtaining the optical and electrical performance parameters of the chip. They estimate that the potential random number generation efficiency is close to 2.8 Gb/s, which is very fast enough for real-time encryption.
Researcher Francesco Raffaelli said that the random number generator consumes only one-tenth the power of other chip-based quantum random number generators.
Compared to the laser pointer-like device using bulk optics technology, the new device is more portable and more stable, thanks in part to factors such as the temperature of the microchip. Using semiconductor manufacturing technology instead of bulk optics technology, it is easier to accurately replicate thousands of identical chips.
The researchers used the external laser pointer, electronics, and measurement tools required by the optical platform to demonstrate QRNG. They are creating portable devices that are the size of a mobile phone, including optical components and the necessary electronic chips. The team believes that more complex systems will achieve higher levels of integration, confidence comes from device size, ease of use, robustness, and low-power operation, as well as more and more industries using silicon photons. Device.
The research team said its QRNG can be directly integrated into silicon-based devices such as Quantum Key Distribution (QKD) systems. The team believes that QRNG can also find other applications that meet the needs of SOI devices for low-impact, high-random numbers.
“Although the electronic control part is not yet complete, we have integrated all the optics needed for device design on a single chip,” Raffaelli said. “Use the device alone or integrate it into other portable devices to protect information security in the future. And personal privacy will play a major role.