著者

Tadao Nagatsuma

出版者

一般社団法人 電子情報通信学会

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

vol.8, no.14, pp.1127-1142, 2011 (Released:2011-07-25)

参考文献数

53

被引用文献数

32 162

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A number of technical breakthroughs in electronics and photonics made since the early 1990s have started to bring terahertz (THz)-wave technologies from laboratory demonstrators to industrial applications such as non-destructive testing, security, medicine, communications, etc. This paper overviews the latest progress in THz-wave technologies in terms of components such as sources and detectors, and system applications, and discusses future challenges towards market developments.

著者

Atsushi Oshiro Naoki Nishigami Takumi Yamamoto Yosuke Nishida Julian Webber Masayuki Fujita Tadao Nagatsuma

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Electronics Express (ISSN:13492543)

巻号頁・発行日

pp.18.20210494, (Released:2021-12-07)

参考文献数

30

被引用文献数

9

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In modern optical communications, pulse amplitude modulation 4 (PAM4) is employed to achieve higher data rates than that achieved by conventional non-return-to-zero format. Meanwhile, there is an increasing interest to convert wired connections to wireless in data centers using high-speed millimeter-wave and terahertz (THz) links. Here, we introduced the PAM4 modulation for THz wireless communications using a resonant tunneling diode (RTD) receiver. Compared with a Schottky-barrier diode receiver, the RTD receiver has higher sensitivity, and a stronger nonlinearity at low input power when it is operated with an amplified detection scheme. We achieved 24-Gbaud (48-Gbit/s) transmission in the 300-GHz band with a quasi-real-time digital signal processing (DSP), which is the fastest PAM4 wireless communication without an offline DSP to the best of our knowledge.

著者

Hai Huy NGUYEN PHAM Shintaro HISATAKE Tadao NAGATSUMA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Electronics (ISSN:09168516)

巻号頁・発行日

vol.E98-C, no.8, pp.866-872, 2015-08-01

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We demonstrate the characterization of a horn antenna in the full F-band (90 ∼ 140 GHz) based on far-field transformation from near-field electro-optic (EO) measurement. Our nonpolarimetric self-heterodyne EO sensing system enables us to simultaneously measure the spatial distribution of the amplitude and phase of the RF signal. Because free-running lasers are used to generate and detect the RF signal, our EO sensing system has wide frequency tunability. Owing to the stable and reliable amplitude and phase measurements with minimal field perturbation, the estimated far-field patterns agree well with those of the simulated results. We have evaluated the estimation errors of the 3-dB beamwidth and position of the first sidelobe. The largest standard error of the measurements was 1.1° for 3-dB beamwidth and 3.5° for the position of first sidelobe at frequency 90 GHz. Our EO sensing system can be used to characterize and evaluate terahertz antennas for indoor communication applications such as small-size slot array antennas.