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Low-temperature-grown GaAs (LT-GaAs)-based Fabry-Pérot cavity photoconductors, designed for RF and THz optoelectronics applications using1550 nm lasers, are studied. The sub-sampling of continuous waves at frequencies up to 300 GHz is presented. The duty-cycle-limited conversion losses measured up to 67 GHz show that this GaAs-based photoconductor behaves as a nearly perfect photoswitch controlled...
This paper presents high-efficiency Unitravelling carrier photodiodes for THz communications. Using high-level modulation schemes, QAM-16 and 32 Gbit/s data-rate is obtained using these devices, that combine high power level and linear behavior, mandatory for high-spectral efficiency data links in the THz range.
We study low-temperature-grown GaAs (LT-GaAs) based ultrafast Fabry-Pérot cavity photoconductors, designed for THz optoelectronics applications using 1550 nm pulsed lasers. We present here, as a proof of concept, the under-sampling of continuous RF waves up to 67 GHz.
We demonstrate multiplexing and demultiplexing for terahertz wireless data links in the 300 GHz band. Demultiplexing of real-time data streams at different carrier frequencies with different data rates is presented, and real-time bit error rates are characterized.
In this paper, an in-situ extraction of the four noise parameters (NFmin, Rn, Γopt) of SiGe HBTs in mmW range (D-Band, 130–170 GHz) is described. Because an external mechanical tuner features high losses in such frequency mmW range, the first idea was to integrate an in-situ tuner directly on the silicon wafer. The concept was then extended in order to integrate more elements on silicon.
This paper presents the development and use of high-efficiency Unitravelling carrier photodiodes for THz communications. Using these devices, high output power is obtained close to the mW level. THz wireless links demonstration is also presented using these devices, using high-level modulation schemes (QAM-16) and 32 Gbit/s data-rate. This result demonstrates the capability of the UTC-PD devices of...
We investigate optical resonant cavities using metallic mirror in order to increase the absorption in low-temperature-grown GaAs (LT-GaAs) based photoconductors operating at telecom wavelength. Two different semi-transparent front mirrors are compared: the first one is a thin gold layer whereas the second one consists of a gold periodic array. We show that the generated photocurrent is 3 times higher...
Heterostructure low barrier diode (HLBD) based on AlGaInAs has been designed, fabricated and characterized for zero-bias millimetre-wave detection. Detectors with different heterostructures and various active areas have been tested in order to optimize their characteristics for low-level radiometric detection. We have measured the microwave performances of HLBD from DC to 220 GHz. A responsivity of...
Gyrotropic hexaferrite materials are believed to be very promising candidates for operation in non-reciprocal devices at terahertz frequencies. We present full permittivity and permeability tensor characterization of different hexaferrite crystalline and ceramic samples in a wide band (0.075–5 THz) using both an original magneto-optical Time-Domain-Spectrometry setup and a magneto-quasi-optical setup...
With the fast increase of mobile data transfers, wireless communications carrier frequencies have entered in the millimeter wave region and now they enter in the submillimeter or terahertz region. In this context photonic-based emitters have several advantages, we will present our communication links results using photomixers at 0.2, 0.4 and 0.6 THz.
A low power 278-GHz CMOS zero-IF heterodyne receiver is presented in this paper. The circuit includes a passive mixer, a baseband amplifier, a 278-GHz triple push sub-harmonic injection locked oscillator and an integrated antenna. The receiver measured maximum conversion gain is −12 dB and the DC power consumption is 47 mW. The on-chip antenna size is 390×280 μm2. The heterodyne receiver is used as...
Thin film grounded coplanar waveguides using Parylene-C and Cyclic-Olefin-Copolymer (COC) as low loss thin film have been fabricated and characterized up to 320 GHz. Attenuation around 1.75 dB/mm has been measured at 300 GHz with ∼5-μm-thick Parylene-C film, close to the attenuation obtained with Cyclo-Olefin Copolymer film of similar thickness.
Ultrafast photoconductors using GaAs implanted by low energy N+ ions (< 55 keV) are fabricated and characterized up to 320 GHz by means of a photomixing experiment. Around 90 μW of output power was obtained at 290 GHz with a 2-μm-diameter photoconductor based on GaAs implanted with a main dose of 1.1×1012 cm−2 and a subsequent annealing at 600°C.
The first quadrature phase shift keying (QPSK) data link at 385 GHz, using a photonic-based terahertz (THz) emission and a double heterodyne THz detection, is reported. The QPSK signalling is investigated up to 16 Gbaud (32 Gbit/s) on a short range distance, with 20 µW received power levels.
In this work, a pulse shaper in coplanar technology intended for the unlicensed band up to the THz region is designed, fabricated, and measured. This broadband frequency range is of great interests as it offers very high data rate communication in local area networks. The technique employs tailored coplanar lines that have been designed using an exact analytical series solution of the synthesis problem...
Narrow linewidth THz generation using a cascaded Brillouin fibre laser structure and a unitraveling carrier photodiode is proposed. Using two distributed feedback lasers separated by > 1 THz with 1 MHz initial linewidth, the linewidth of the realized THz source is found to be < 100 Hz at 1014.7 GHz without use of any active stabilization of the laser cavity or any microwave reference.
In this communication, we study the effect of the position of SRR on the resonance frequency of the planar circuit. The idea is to better control the position of SRR along the Planar Goubau Line (PGL) in order to attain maximum rejection. This result is important for the design of terahertz circuits. As a demonstration of the flexibility and scalability of the designs, we show experimental results,...
We report on Gallium Nitride Self switching Diode used as detector in a terahertz imaging system. We propose to use the ionic implantation to define the nano-channels in the device, leading to an improved sensitivity in the mm-wave/THz regime. Preliminary results are given at 200 GHz.
We propose a 600 GHz data transmission of high definition television using the combination of a photonic emission using an uni-travelling carrier photodiode and an electronic detection, featuring a very low power at the receiver. Only 10 nW of THz power at 600GHz were sufficient to ensure real-time error-free operation. This combination of photonics at emission and heterodyne detection lead to achieve...
It is shown from accurate on-wafer measurement that a low-temperature-grown GaAs photoconductor using a metallic mirror Fabry-Perot cavity can serve as highly efficient optoelectronic heterodyne mixer in the terahertz frequency range. Conversion losses of 22 dB at 100 GHz and ∼27 dB at 300 GHz were measured, which is an improvement by a factor of about 40 dB as compared with the previous values obtained...
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