Learn More
We demonstrate direct quadrature modulator and demodulator monolithic microwave integrated circuits for future terahertz communications at 300 GHz based on the quadrature phase-shift keying (QPSK) modulation format. For the modulating and demodulating signal, we employed half-Gilbert cell mixers, which provide balanced signaling and moderate performance in(More)
In this paper, we present a microwave photonic technique to produce a noise signal from the microwave to sub-terahertz region with an optical amplified spontaneous emission noise, optical filter, and photodetector. With this scheme, it is easy to control the noise level by simply controlling the input optical noise power. In addition, the output noise(More)
A novel all-optical frequency up-converter utilizing four-wave mixing (FWM) in a semiconductor optical amplifier (SOA) was proposed and experimentally demonstrated. The frequency up-converter converted an optical intermediate frequency (IF) signal (f(IF) = 2.5 GHz) to an optical radio frequency (RF) signal (f(RF) = 35 and 40 GHz) through mixing with an(More)
Tadao Nagatsuma , Akira Kaino, Shintaro Hisatake, Katsuhiro Ajito, Ho-Jin Song, Atsushi Wakatsuki, Yoshifumi Muramoto, Naoya Kukutsu, and Yuichi Kado Graduate School of Engineering Science, Osaka University 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan NTT Microsystem Integration Laboratories, NTT Corporation 3-1 Morinosato Wakamiya, Atsugi, Kanagawa(More)
We present a compact and stable terahertz (THz) vector spectroscopy system using silicon photonics technology. A silicon-based integrated phase control circuit greatly reduces the physical size of the continuous-wave THz spectroscopy system and enhances environmental phase stability. Differential lightwave phase control using two carrier-injection(More)
For continuous millimeter and terahertz-wave applications, a two-mode optical signal generation technique that uses two arrayed waveguide gratings and two optical switch units is presented. In addition to easy and fast operation, this scheme offers broadband frequency tunability and high signal purity with a low spurious mode level. Mode spacing, which(More)
We present a photonic technique for generating a frequency- modulated sub-terahertz signal for non-destructive or noninvasive sensing and imaging applications. Large frequency deviation was achieved by using optical phase modulation and heterodyne photomixing with an uni-travelling photodetector. The operation principle is theoretically derived and(More)