First spin photo detector capable of 10x data transmission speeds for the next-gen AI

TDK Corporation has developed the world's first 'Spin Photo Detector', a photo-spintronic conversion element combining optical, electronic, and magnetic elements that can respond at an ultra-high speed of 20 picoseconds (20 × 10⁻¹² s) using light with a wavelength of 800nm – more than 10X faster than conventional semiconductor-based photodetectors. This new device is predicted to be a key driver for executing photoelectric conversion technology that raises data transmission and data processing speed, particularly in AI applications, while simultaneously lowering power consumption.

As AI evolves, transferring mass amounts of data at higher speeds and with lower power consumption is an inevitable necessity. Electrical signals transfer data between CPU/GPU chips and from and to memory to process data and make calculations. Thus, there is an increasing demand for optical communication and optical interconnects, which deliver high speeds that do not decrease with interconnect distance. Photoelectronic conversion technology is also gaining global interest as a compact fusion of optical and electronic elements.

To manage these challenges, the company adapted its magnetic tunnel junction (MTJ) technology for photonics, which is currently employed in billions of HDD heads. One of the major advantages of this technology is that it does not need crystal growth utilising a single crystal substrate, and the device can be formed regardless of the substrate material. Comparatively, conventional semiconductor-based photo detectors have physical limitations at shorter wavelengths. Because the Spin Photo Detector has a completely different operating principle and employs an electron heating phenomenon, it can operate at ultra-high speeds even when the wavelength is shortened. Also, the operating wavelength range is wide, and it has been confirmed to operate from visible to near-infrared. The company has successfully demonstrated the spin photo detector with Nihon University in Japan, a research pioneer for the measurement of ultrafast phenomena of magnetic material.

Further, with the ability to detect visible light at high speeds, the spin photo detector will be useful in applications projected for future growth, such as devices for AR/VR smart glasses and high-speed image sensors. While conventional semiconductor photo-sensing devices have weak cosmic-ray resistance, MTJ elements are also known for strong cosmic-ray resistance and are expected to be utilised as light-detecting elements in aerospace applications.