Tuesday , August 16 2022

Millimetric waves to the last mile


Millimetric waves to the last mile

ETH The students in Zurich can create a modulator, which can be converted directly into lightweight pulse optical fibers that can be transmitted in millimeter waves. This may include the "last mile" faster and cheaper than the home-based socket.

Photo Title: The "last mile" is also the most demanding for home internet connection. The new modulator is a viable alternative. Data transmitted through millimeter waves (red arrows) can be converted directly into the pulse (yellow) pulse for optical fibers. (Scenes: Salamin Y and others Nature Photonics 2018)

High frequency oscillations are ideal for fast data transfer. They can be transported by optical fibers and transported hundreds of billions of bits per second (gigabit) per second. However, the "last mile" from the central fiber-optic cable to the home Internet outlet is the most difficult and expensive. Some alternatives, such as 4 / 5G mobile telephony, are cheaper, but they can not provide all users simultaneously with the very high rate of transmission required for applications that want to open the data.

Professor Jurg Leighold, of the ETH Zurich Institute of Electromagnetic Fields and his colleagues, has now developed a new light modulator with the support of colleagues from the University of Washington at Seattle, Washington, DC, which will allow covering the ultimate highway in the future with high-speed microwaves – millimeter waves, effective and cheap – and therefore high data transmission speed.

Electronic light bulb modulator

Data encoded in optical fibers are very fast and, therefore, more expensive – with electronic components, with changes in light intensity to millimeter waves. In the opposite direction, the millimeter waves must first be obtained by antenna, then merged into a base lane and then inserted into the light modulator, which transmits the data from the radio waves to the light pulses.

Leuthold and his colleagues have now been able to design a lightweight modulator that works on batteries and electronics. "This makes our modulator completely dependent on external power supplies, and it's too small, which can be set to any bulb. After that, he can receive data from private houses through microwave signals and deliver them directly to the central optical fiber, "explains Yannik Salamin, a doctoral student who made an important contribution to the development of a new modulator.

Modulation by Plasmons

The modulator made by ETZ researchers consists of a chip that measures less than millimeters, including a microwave antenna. This antenna receives millimeter waves and transforms them into electrical voltage. The voltage operates in the center of the chip in a slim cell – the modulator's true heart. The narrow aperture, which is less than one hundred nanometers long and a few micrometers long, is filled with electrically sensitive material. The light beam derived from the fibers is given to this curve. Inside the nozzle is called the plasmon, rather than the electromagnetic wave, which differs from the light differential cable or air. Plasmons – electromagnetic fields, hybrid and electric current oscillations on the surface of the metal. Thanks to this quality, they can be much closer than bright waves.


ETH is a new modulator developed in Zurich with a milimeter wave (blue) antenna and transmits into the small cell into optical signals (red). The device is powerless and has a size less than millimeters. (Views: ETH Zurich / Jürg Leuthold)

The smallest electric field made of an electrically sensitive ("linear") antenna material in the slot strongly affects the distribution of plasmons. The impact on the wave oscillation phase is maintained when plasmons become light waves at the end of the section. Thus, the data bits in millimetric waves are transmitted directly to light waves – without electronics and without any external power rotation. In laboratory experiments with microwave signals in 60 gigaherers, researchers have been able to display data rates up to 10 gigabits per second and range from one meter to 20 gigabits per second in five meters.

Cheap and versatile

Along with small amounts of energy and less energy, the new modulator has a number of additional benefits. "Direct transformation from millimeter waves to light waves makes our modulator particularly versatile in the frequency and specific format of data coding," Leuthholt said. In fact, the modulator is based on the new 5G technology and future industry standards, the speed of transmission of up to 300 Gigahert wavelength and teraherz frequencies and up to 100 gigabits per second. Moreover, it can be made by traditional silicon technology, and, therefore, relatively inexpensive.

Finally, Leuthold can be sure of the users who are concerned about electromagnetic radiation. Millimetric waves that are evenly distributed in all directions, except radio waves or wifi modems, are for external transfer and can only be distributed between the roof antenna and the light pole in the range of up to twenty centimeters in the light diameter. This significantly reduces the power required to transport compared to other wireless technologies. It also eliminates the typical problems of WiFi modems and their signals can reach each other.

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