39th Int. Conf. on Infrared, Millimeter, and THz Waves
September 14-19, 2014
The University of Arizona, Tucson, AZ
M3/B - 3. Communications II - 4. Astronomy and Planetary Science I
Monday, September 15, 2014 2:00 pm to 3:30 pm
Room: Catalina Room
Chairperson: Christopher Walker
2:00 pm 2:00 pm : 30-Gbit/s Wireless Transmission Over 10 Meters At 300 GHz
Presenter: Tadao Nagatsuma

Recently, there has been a growing interest in the application of terahertz (THz) waves, whose frequencies range from 100 GHz to 1 THz, to ultra-broadband wireless communications . Photonic techniques have been efficiently employed to generate and modulate THz carrier signals. Real-time and error-free transmission experiments have so far been demonstrated at bit rates of 40 Gbit/s and 48 Gbit/s for a single polarization system and a polarization-multiplexed one, respectively, using a photonics-based transmitter and a direct detection receiver at 300 GHz at a typical link distance of 0.5 meters.
In order to increase not only the bit rate but also the transmission distance, introduction of coherent techniques for generation and detection of THz carrier signals is effective and practical. In this paper, we will present 300-GHz-band wireless link based on photonics technologies, and demonstrate a real-time and error-free transmission at a bit rate of 30 Gbit/s with a transmission distance of 10 meters.
The photonics-based transmitter consists of an optical frequency comb generator, an integrated optical filter/combiner and a photodiode module, while the receiver is a sub-harmonic mixer pumped by local oscillator (LO) signal at 150 GHz. THz beams are collimated by aspheric Teflon lenses (100-mm diameter) over the link distance of 10 meters.
BER characteristics and an eye diagram were measured at a bit rate of 30 Gbit/s and a link distance of 10 meters. Error-free (BER<10-11) performance was confirmed for the photocurrent of ~8 mA, which corresponds to ~90-W output power of the transmitter.

Tadao Nagatsuma - Osaka University
Yasuyuki Yoshimizu - Osaka University
Yuu Yasuda - Osaka University
Kazuki Oogimoto - Osaka University
Shogo Horiguchi - Osaka University
Yusuke Minamikata - Osaka University
Shintaro Hisatake - Osaka University
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2:30 pm 2:30 pm : Anisotropic THz Plasmonic Filter Created Using A K-Space Design Technique
Presenter: Andrew Paulsen

Wireless communication systems in the terahertz frequency range promise to dramatically increase available bandwidth in the electromagnetic spectrum. These wireless systems will require filtering techniques capable of operating in this relatively unused part of the spectrum. In pushing towards more advanced filtering techniques, we demonstrate a terahertz filter design methodology based upon k-space that shows more complex filters. Using this methodology we show a highly anisotropic filter where transmittance is varied by 80 percent with rotation in polarization angle. Filters have found application in virtually every field of science and engineering. The versatility and high performance of a wide range of filters enable the interconnected society we enjoy today. While well-defined filter design methodologies exist for much of the electromagnetic spectrum, the THz region of the spectrum lags behind in filter complexity and lacks the same caliber of design tool found in other frequency regimes. Various approaches to creating filters in the THz region have been shown. While different types of filters have been demonstrated an approach is still needed that can show versatility in designing arbitrary frequency responses within a single design methodology. In this submission we show a THz filter design methodology based on k-space structures allowing for greater versatility in creating different classes of filters with one approach. In this design methodology the designer is free to define a desired frequency response which is then mapped into k-space using the simple relationships between the wave vector and frequency, k=2Ì/c. The k-space representation is then transformed into the spatial domain. The resulting spatial image is the digital representation of a physical device that will possess the designed frequency response. We then fabricate the device using a conventional ink-jet printer with conductive silver ink and resistive carbon ink to directly print out the digital spatial image.

Andrew Paulsen - University of Utah
Ajay Nahata - University of Utah
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2:45 pm 2:45 pm : 20-Gbaud QPSK Coherent Radio Transmission At 325 GHz With High-Gain Antennas
Presenter: Atsushi Kanno

High-speed coherent transmission at 325 GHz is successfully demonstrated with a 20-Gbaud QPSK signal. A frequency-locked terahertz signal can be provided by an optical-modulation-based optical frequency comb signal. A high-gain antenna with a gain of 46 dBi is suitable to extend the transmission distance up to 15 m without requiring a terahertz amplifier.

Atsushi Kanno - National Institute of Information and Communications Technology
Toshiaki Kuri - National Institute of Information and Communications Technology
Isao Morohashi - National Institute of Information and Communications Technology
Iwao Hosako - National Institute of Information and Communications Technology
Tetsuya Kawanishi - National Institute of Information and Communications Technology
Yuki Yoshida - Osaka University
Kenichi Kitayama - Osaka University
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3:00 pm 3:00 pm : X-Spec: A Multi-Object, Trans-Millimeter-Wave Spectrometer For CCAT
Presenter: Scott Chapman

X-Spec is a multi-beam, R=400-700 survey spectrometer covering 190-520 GHz under development for CCAT. It measure the bright atomic fine-structure and molecular rotational transitions that cool galaxies' interstellar gas, in particular, the 158 µm rest-frame [CII] transition which is accessible from z=9.5 to z=3.5, With the wide bandwidth and multi-object capability, X-Spec / CCAT will be more powerful than ALMA for redshift-blind galaxy surveys and tomographic intensity mapping. X-Spec uses SuperSpec filterbank spectrometer technology with TiN KIDs. Because the density of sources is small, galaxy follow-up will be most efficient with a front-end steering unit which we have prototyped. Our baseline instrument concept has 84 steered beams arrayed over the 1 degree CCAT field, each beam couples to 4 chips (2 bands x 2 polarizations) each chip with ~500 detectors, making a total of ~170,000 KIDs in the full instrument.

Scott Chapman - Dalhousie University
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3:15 pm 3:15 pm : 10 Meter Sub-Orbital Large Balloon Reflector (LBR)
Presenter: Christopher Walker

Under the auspices of the NASA Innovative Advanced Concepts (NIAC) Program our team is developing and demonstrating key technologies required to realize a suborbital, 10 meter class telescope suitable for operation from radio to THz frequencies. The telescope consists of an inflatable, half-aluminized spherical reflector deployed within a much larger carrier balloon - either zero pressure or super pressure. The realization of a large, space-based 10 meter class telescope for far-infrared/THz studies has long been a goal of NASA. Such a telescope could study the origins of stars, planets, molecular clouds, and galaxies; providing a much needed means of following-up on tantalizing results from recent successful missions such as Spitzer, Herschel, and SOFIA. However, by combining successful suborbital balloon and ground-based telescope technologies, the dream of a 10 meter class telescope free of 99% of the Earth's atmospheric absorption in the far-infrared can be realized. The same telescope can also be used to perform sensitive, high spectral and spatial resolution limb sounding studies of the Earth's atmosphere in greenhouse gases such as CO, ClO, O3, and water, as well as serve as a high flying hub for any number of telecommunications and surveillance activities.Our concept study focuses on using LBR as a suborbital platform, but it also has the potential of being deployed in orbit.

Christopher Walker - University of Arizona
Stefan O'Dougherty - University of Arizona
Brian Duffy - University of Arizona
Brandon Swift - University of Arizona
Jenna Kloosterman - University of Arizona
David Lesser - University of Arizona
Casey Honniball - University of Arizona
Abram Young - University of Arizona
Craig Kulesa - University of Arizona
William Peters - University of Arizona
Steve Smith - Southwest Research Institute
James Noll - Southwest Research Institute
William Perry - Southwest Research Institute
Pietro Bernasconi - JHAPL
Paul Goldsmith - JPL
Christopher Groppi - Arizona State University
Hamdi Mann - Arizona State University
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