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By combining a UTC-PD as a THz emitter and a 400 GHz Schottky-based heterodyne detection, we realized an indoor THz link working up to 22 Gbps at 400 GHz carrier frequency with ultra-low THz power. The eye diagram at receiver is clearly opened are the system is working with only 1 µW received THz power.
A dual-frequency laser coupled to a unitravelling carrier photodiode is used to produce a highly coherent THz wave. THz signal is detected by a subharmonic mixer coupled to an electrical spectrum analyzer. All components involved in this experiment operate at room temperature and no active stabilization is used. The measured linewidth is better than 30 kHz and tunable from DC to 1 THz. The dynamic...
A Gbit/s photonic transmitter with an integrated antenna system has been built and used to demonstrate a very high-speed wireless indoor network. The system, developed by researchers at Institute of Electronics, Microelectronics and Nanotechnology (IEMN) and Atom, Molecules and Laser Physics (PhLAM) laboratories, part of the French National Centre of Scientific Research (CNRS) based at the University...
We report the transfer of a GHz modulation from an optical carrier at telecom wavelengths to a free space THz beam. THz radiation-tunable from 300 GHz to 1.2 THz- is generated by mixing two telecom lasers with an offset frequency in an ultrafast In0.53Ga0.47As photoconductive device coupled to a broadband antenna. A maximum modulation rate of 20 GHz has been achieved, and the bandwidth is independent...
We report the generation of continuous terahertz waves from microwave frequencies up to 2 THz obtained by photomixing two optical waves at 1.55-mum wavelengths in an optimized ion-irradiated In0.53Ga0.47As interdigitated photomixers. Output powers greater than 40 nW at 0.5 THz and 10 nW at 1 THz have been achieved. The optimum excitation conditions regarding optical power and bias voltage are discussed.
The fabrication of InGaAs/InP uni-travelling-carrier photodiodes integrated with broadband horn antennas and demonstration of photomixing up to 1.8THz are reported. A radiated power of 1.1 μW at 940 GHz was measured for a photocurrent of only 2.75 mA (50 mW optical power), demonstrating the high efficiency of the device. The conversion efficiency obtained has been increased by more than a decade compared...
A horn-antenna is integrated on a microstrip waveguide QCL emitting at 2.0 THz. This allows a better impedance match to free space, which improves substantially the directivity of the beam and the radiation outcoupling.
We report on three issues of left handed metamaterials targeting the terahertz spectral region (far- and mid-infrared). First, we show that it is possible to design a broadband negative index metamaterial by combining the respective advantages of current loops (the C-shaped pattern of split ring resonators) responsible of artificial magnetism and of continuous wires. Negative refraction was here demonstrated...
We present a time-domain terahertz spectroscopy set up based on Er:fiber laser which delivers pulses at 1.55 mum wavelength and that integrates photoconductive antennas made on heavy ion-irradiated In0.53Ga0.47As material as emitter and detector. A detailed study of the effect of the carrier lifetime on the terahertz signal characteristics has been performed. Improvements in bandwidth and in average...
We report the first demonstration of a terahertz photomixer made of ion-irradiated In0.53Ga0.47As lattice-matched to InP and fiber-optic coupled with the 1.55 μm wavelength drive lasers. The detected signal is at the most 15 dB lower than the one obtained from similar photomixers fabricated from low-temperature-grown GaAs.
Summary form only given. Promising quantum-dot devices such as lasers and infrared photodetectors have lead to an intensive study of the optical properties of quantum dots. The physics of carrier dynamics in quantum dots is of particular importance for devices especially because a drastic slow down of the relaxation is expected due to the discrete nature of the electronic energy states (phonon bottleneck...
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