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1

Digital communication : optical vs. THz links

Marczewski Jacek

Opto-Electronics Review

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2020

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Vol. 28, No. 3

176--181

EN

The paper presents a comprehensive look at the perspectives on the use of THz in digital communication systems. The publication aims to focus on arguments that justify a significant increase in the frequency of radio links and their integration with fibre-based networks. Comparison of THz links with their microwave and optical counterparts is discussed from basic physical limitations to technological constraints. Main attention is paid to the available channel capacity resulting from its bandwidth and signal-to-noise ratio. The short final discussion is about technology platforms that seem to be crucial to the availability of suitable THz sources. According to the author, the biggest advantage of using bands in the range of several hundred GHz for a digital data transmission is their use for mobile communication over short distances, as well as for broadband indoor links. However, these applications require a development of compact electronic THz sources with low noise and power reaching single watts. This is beyond the range of the most popular silicon-based technology platform, although a significant progress can be expected with the development of technologies based on wide bandgap semiconductors. Fibre optic connections remain the unquestioned leader in communication over long distances and permanent links.

2

Synthesis and characterization of a new type of electro-optic polymer without carbon main chains

Zhang Y., Qiu C., Li Y., Zhang W, Xuan W

Materials Science Poland

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2014

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Vol. 32, No. 3

402--407

EN

A new type of electro-optic (EO) polymer is prepared in this work. The main chain of the EO polymer is made of polyphosphazenes, and the side chain consists of carbazole based nitro azobenzene. The principle and method of preparation are given and the characteristics of this material are studied in details. The polymer with an EO coefficient of 35 pm/V has fine stability and can be easily processed. It also shows photoconductivity due to the carbazole group. This polymer thin film is obtained through performance improvement. Terahertz (THz) wave can be detected using the device, which is made of the new polymer. Owing to its fascinating properties, this new type of EO polymer has the potential to be widely applied in photorefractive materials as well as for emission and detection of THz radiation.

3

Właściwości i zastosowania nematycznych ciekłych kryształów w technologii terahercowej

Chodorow U., Parka J.

Biuletyn Wojskowej Akademii Technicznej

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2013

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Vol. 62, nr 1

13-30

PL

Prace nad technologią terahercową (THz) prowadzone są już od przeszło trzech dekad, podczas gdy badania nad wykorzystaniem ciekłych kryształów (CK) w zakresie THz trwają dopiero od dekady. W artykule przedstawione zostały wyniki pomiarów spektralnych CK w obszarze Thz. Opisano wybrane właściwości komercyjnie dostępnego związku CK o symbolu 5CB oraz dwóch mieszanin CK o nazwach 1832B i 1825. Korzystając z dostępnej literatury, zostało wybranych i omówionych kilka urządzeń modulujących promieniowanie THz, w których jako elementy przestrajalne wykorzystane zostały ciekłe kryształy.

EN

Works on terahertz (THz) technology have been conducted for over three decades while research on the use of liquid crystals in the THz range lasted only a decade. In the paper, the results of spectral measurements of LC in the THz range are presented. Selected properties of a commercially available LC compound with the symbol 5CB and two LC mixtures called 1832B and 1825 are described. Using available literature, several devices, which modulate the THz radiation, were selected and discussed. In these devices, liquid crystals were used as tunable elements.

4

Detection of terahertz and sub-terahertz wave radiation based on hot-carrier effect in narrow-gap Hg₁₋xCdxTe

Zabudsky V., Dobrovolsky V., Momot N.

Opto-Electronics Review

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2010

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Vol. 18, No. 3

300-304

EN

We have proposed and developed terahertz and subterahertz wave detector using hot-carrier effect in narrow-gap Hg₁₋xCdxTe. Epitaxial Hg₁₋xCdxTe -layers were integrated into dipole antennas. The response of Hg₁₋xCdxTeTe hot-electron bolometer was measured in the range of frequencies 0.037-1.58 THz, in the temperature region T = 68-300 K at various bias currents. A bolometer theoretical model was developed and the experimental results confirm the model main conclusions.