Data encoding on terahertz signals for communication and sensing

Moller, L.; Federici, John F.; Sinyukov, Alexander M.; Xie, Chongjin; Lim, Hee C.; Giles, Randy

doi:10.1364/ol.33.000393

Cited by 56 publications

(20 citation statements)

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“…Due to the high resistivity and extremely short carrier trapping time (~200 fs) of LTGGaAs, carrier drift time, dark current and depletion layer thickness are of considerably less importance for the construction of high-power, highspeed LTG-GaAs-based photodiodes. LTG-GaAs-based metal-semiconductor-metal photodiodes [62][63][64], photoconductive dipole antennas (PDAs) [8,65,66], and p-i-n photodiodes [59,67] with extremely high saturation peak output power and wide O-E bandwidth have been demonstrated. High-power LTG-GaAs-based photodiodes have been used with planar-circuit broadside antennas, including planar dipole, slot and spiral antennas [68].…”

Section: Millimeter-wave Photonic Transmittersmentioning

confidence: 99%

“…As can be seen from the figure, the slot antenna provides much higher output power in the 1-2 THz frequency regime compared with the spiral antenna due to the characteristic resonance of the slot antenna [68]. These LTG-GaAs-based PDAs have been successfully used for wireless linking at center frequencies of around 0.3 THz [65,66]. However, the data rate so far achieved is low (~1 Mbit s -1 ) [65] and limited by the repetition rate of the Ti:sapphire laser (~80 MHz).…”

Section: Millimeter-wave Photonic Transmittersmentioning

confidence: 99%

“…These LTG-GaAs-based PDAs have been successfully used for wireless linking at center frequencies of around 0.3 THz [65,66]. However, the data rate so far achieved is low (~1 Mbit s -1 ) [65] and limited by the repetition rate of the Ti:sapphire laser (~80 MHz). In addition, the internal quantum efficiency of these LTG-GaAs-based devices is poor, usually less than 10%, due to the short carrier trapping time.…”

Section: Millimeter-wave Photonic Transmittersmentioning

confidence: 99%

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Millimeter-wave photonic wireless links for very high data rate communication

2011

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T he most useful wireless communication band is located in the frequency range of 0.3-3.5 GHz for reasons of compact antenna size, low propagation loss and good penetration through buildings [1]. However, wireless carrier frequencies are being pushed higher due to emerging high-bandwidth applications, which include next-generation smart cell phones [1] and wireless linking for three-dimensional super high-definition television [2]. As a result, the millimeter-wave (MMW) bands at 60 (V-band), 120 (D-band) and even higher than 300 GHz are beginning to attract attention due to their 'unlicensed' usage [2][3][4][5][6][7][8].Several key front-end components have been developed employing the already mature silicon-based complementary metal-oxide-semiconductor (CMOS) integrated-circuit (IC) technology for wireless communication in the V (50-75 GHz) and W (75-110 GHz) bands or even higher operating frequencies for wireless communication [9]. Recently, a 60 GHz CMOS transceiver module [10] and system comprised of antennas, 60 GHz power amplifiers, local oscillators and baseband ICs has been commercially developed by SiBEAM (USA). In addition, advanced InP-based high electron mobility transistors (InP-HEMTs) and heterojunction bipolar transistors have been used to develop some high-speed ICs and key components that operate at 125 GHz [11,12] or greater than 300 GHz [13,14] for >1 Gbit s -1 wireless communication systems.However, MMW signals suffer substantial propagation loss in free space [8]. This problem and their inherent straight-line path of propagation affect connections and synchronization between the different parts of the whole communication system [15]. A promising solution to overcome this problem is the radio-over-fiber (RoF) technique [3,4,16,17], in which the MMW local-oscillator signal and data are both distributed through a low-loss optical fiber and only radiated over the last mile to the end user. Figure 1 shows a schematic representation of this approach, illustrating the motivation and working principles of two MMW-over-fiber communication systems. Figure 1(a) shows the additional electrical-to-optical (E-O) and optical-to-electrical (O-E) conversion processes used in the central office and base station, respectively. The optical MMW signal is distributed remotely through a low-loss fiber from the central office to several base stations, effectively eliminating the huge propagation loss of the MMW signal that occurs in an electrical transmission line or free space.

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Section: Millimeter-wave Photonic Transmittersmentioning

confidence: 99%

Section: Millimeter-wave Photonic Transmittersmentioning

confidence: 99%

Section: Millimeter-wave Photonic Transmittersmentioning

confidence: 99%

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Millimeter-wave photonic wireless links for very high data rate communication

2011

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“…Over the past two decades, there has been a tremendous growth in THz technology. Many potential applications, including medical diagnostics [2,3], spectroscopy of biomolecules [4], security [5][6][7], and communications [8,9], have been explored. A number of significant studies have motivated the need for THz spectroscopy of liquids, including characterizing hydration state in solution [10], investigation of inflammable liquids [11], solvent diffusion in polymers [12], solvation dynamics of liquid mixtures [13,14], spectroscopy of liquid using evanescent field of a silicon waveguide [15], characterization of aqueous alcohol solutions in bottles [16], microfluidic devices for THz spectroscopy of biomolecules [17], and spectroscopy of liquids using double-modulated differential time-domain spectroscopy [18].…”

Section: Introductionmentioning

confidence: 99%

Sensing the hygroscopicity of polymer and copolymer materials using terahertz time-domain spectroscopy

2009

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“…One of the key components is the modulator. Liu et al and Möller et al have demonstrated direct modulation of terahertz sources by applying a modulation signal onto the photoconductive antennas in a terahertz time domain spectroscopy system [2,3]. A modulation rate of 1 Mbit/s and bandwidth of 23 kHz was achieved.…”

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confidence: 99%

Terahertz free space communication based on acoustic optical modulation and heterodyne detection

Saha

Bernassau

et al. 2011

Electron. Lett.

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A terahertz free space communication system based on acoustic optical modulation and heterodyne detection is demonstrated. A high resistivity silicon acoustic optical modulator was used to modulate a continuous terahertz wave at 2.52 THz. A pyroelectric detector was used to detect the modulated terahertz signal via heterodyne detection mode. A modulation frequency of 937 kHz and sampling rate of 1 kbit/s was achieved.Introduction: In the last twenty years, research in terahertz technologies (0.1 -10 THz) has grown significantly owing to its promising applications such as nondestructive imaging, spectroscopy and wireless communication. Although terahertz imaging and spectroscopy have been intensively investigated, only a few studies have been reported regarding terahertz wireless communications. This is due to the technical barriers that have to be overcome for developing suitable sources, modulators and receivers. Yet the advantages of terahertz communication over conventional microwave wireless are obvious [1]. Terahertz systems have the potential to provide a much broader bandwidth, more directional transmission (useful to reduce the size of the antenna) and more secure information communication due to the short transmission distance.Considerable work has been carried out into components and systems for terahertz communications [2 -7]. One of the key components is the modulator. Liu et al. and Möller et al. have demonstrated direct modulation of terahertz sources by applying a modulation signal onto the photoconductive antennas in a terahertz time domain spectroscopy system [2,3]. A modulation rate of 1 Mbit/s and bandwidth of 23 kHz was achieved. External modulation based on semiconductor devices with a quantum-well structure has also been demonstrated [4,5]. However, the operating temperature must be extremely low, which is not suitable for practical applications. For room-temperature operation, Kleine-Ostmann reported a terahertz semiconductor modulator with a modulation frequency of 23 kHz and demonstrated audio transmission based on this modulator in THz TDS [6]. Chen et al. reported a terahertz modulator based on all electrically driven active metamaterial. A modulation frequency up to 2 MHz was achieved [7].In this Letter, we demonstrate a potential signal communication system at room temperature using an acoustic optical modulator (AOM) and a pyroelectric heterodyne detector. The AOM provides a simple method for modulation over a broadband frequency range. In an AOM, a travelling acoustic wave at frequency v A causes the incident terahertz wave at frequency of v T to diffract, as shown in Fig. 1a. The diffracted beam is frequency modulated by the acoustic wave at v A . The diffracted beam together with the undiffracted beam are focused onto the pyroelectric detector that works in a heterodyne mode. Pyroelectric detectors have broad detection bandwidth at room temperature, from visible to terahertz frequencies. In addition, they are capable of responding to modulation frequencies of the order of several ...

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Data encoding on terahertz signals for communication and sensing

Cited by 56 publications

References 0 publications

Millimeter-wave photonic wireless links for very high data rate communication

Millimeter-wave photonic wireless links for very high data rate communication

Sensing the hygroscopicity of polymer and copolymer materials using terahertz time-domain spectroscopy

Terahertz free space communication based on acoustic optical modulation and heterodyne detection

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