Tag Archives: photonics

Terahertz Electronics – Way To Bridge The largely-untapped Region Between 100GHz and 10THz

The terahertz (THz) region, which is based on 1THz frequency, separates electronics from photonics and has been difficult to access for ages. Semiconductor electronics cannot handle frequencies equal to or greater than 100GHz due to various transport-time related limitations. In other hand, photonics devices fail to work below 10THz as photon’s energy significantly drops to thermal energy. Terahertz Electronics (TE) is a new technology that extends the range of electronics into the THz-frequency region.

The Terahertz Gap
The Terahertz Gap

The main goal of Terahertz Electronics is to build a bridge between low-frequency “Electronics” and high-frequency “Photonics”. Since these devices use photon-electron particle interactions, as photon energy “hv” decreases below thermal energy “kT”, the device ceases to operate efficiently unless it is cooled down. At the low-frequency end, electronics cannot operate above 100GHz as transport time is dependent on drift and diffusion speeds of electrons/holes. As a result, a large region between 100GHz and 10THz remained inaccessible. Terahertz Electronics solves this problem efficiently by cleverly incorporating electronics with photonics.

Terahertz electronics technology offers practical applications in high-speed data transfer, THz imaging, and highly-integrated radar and communication systems. Surprisingly enough, It does not use semiconductors. Instead, it is based on metal-insulator tunneling structures to form diodes for detectors and ultra-high-speed transistors for oscillator based transmitters.

One drawback of the Terahertz Electronics is, it requires high-frequency radiation sources. Lack of a small, low-cost, moderate-power THz source is one of the main reasons that THz applications have not fully materialized yet. Scientists are trying to find a solution to this problem. They created a compact device that can lead to portable, battery-operated sources of THz radiation. This new solid-state T-ray source uses high-temperature superconducting crystals that contain stacks of Josephson junctions. So, even a small voltage, around two millivolts per junction, can induce frequencies in the THz range.

Mercury arc lamps generate light in terahertz
Mercury arc lamps generate light in terahertz

TE devices are extremely fast and they are made entirely of thin-film materials—metals and insulator. Hence, it is possible to fabricate Terahertz Electronics devices on top of complementary metal oxide semiconductor (CMOS) circuitry—a technology for creating integrated-circuits circuitry or on an extensive variety of substrate materials. In TE devices, charge transport through the junction occurs via electron tunneling. Further research and development will make Terahertz Electronics a reality in not-so-distant future.

290Hz Narrowband Laser On Chip For Numeros Photonic Applications

Researchers from the MESA+ research institute at University of Twente have collaborated together with the provider company of the customized microsystem solutions “LioniX International” to achieve the lowest bandwidth tunable diode laser on a chip.

The newly-developed laser operates in the IR region at 1550 nm with an 81 nm tuning range, which means that users can choose the color of the laser themselves, within a broad range. The laser is an integrated InP-Si3N4 hybrid laser consists of two different photonic chips, optically connected to each other.

Photonics is a key technology that makes numerous other innovations possible. So that, scientists and researchers are making big efforts at this field including deployment of photons for transporting and processing data.

To make photonic chips function as efficient as possible, we need to be able to control the light signals. Which means that all transmitted light particles should have the same frequency and wavelength as possible. The university researchers have succeeded developing a tiny laser on a chip with a maximum bandwidth of just 290 Hertz.

Our signal is more than ten times more coherent – or clean – than any other laser on a chip.
~ Professor Klaus Boller, the research leader

This record laser will have countless applications especially in fiber optic communications that require high data rate. This applications includes 5G mobile networks, accurate GPS systems and sensors for monitoring the structural integrity of buildings and bridges.

You can find out more details here.