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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.
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...
We present poly-silicon depletion-based optical modulators realized in a 65 nm CMOS platform for monolithic integration with electronics. Speeds up to 12.5 Gbit/s can be achieved with 5 dB insertion loss and 2.3 dB extinction ratio.
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.
We demonstrate a W-band bolometer based on a platinum nano-strip which is integrated with a waveguide probe on a polymer substrate. We measure a high thermal response of 49000 K/W thanks to the small size of the Pt resistor and the thermal properties of the polymer. Furthermore, its small thermal capacity allows to decrease the time constant to 2.2 ms. A good matching in the entire W-band is achieved...
This work presents the design, fabrication and characterization of a system based on thin film technology for the selective detection of the natural fluorescence of Ochratoxin A. To this aim, the system optically couples an amorphous silicon photosensor with a long pass multi-dielectric filter, deposited on glass substrates. In particular, the filter rejects the wavelengths coming from the excitation...
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.
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...
We investigated a coherent THz link at 200 GHz, with variable data rate up to 11 Gbit/s, featuring the combination of a quasi-optic UTC-PD emitter and a high sensitivity electronic receiver. This coherent link relies on an optical frequency comb generator at emission to produce an optical beat note with 200GHz separation. BER testing has been carried out using an indoor link configuration and the...
Here, we demonstrate the possibility of employing a novel low-loss dielectric material as substrate for free-space THz devices through the design, fabrication and characterization of broadband high-transparency high-pass mesh filters. Time-domain spectroscopy measurements show that a transmittance higher than 75% is achieved over a bandwidth of 1 THz.
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.
It is shown that a continuous wave output power reaching 1.8 mW at 252 GHz can be generated by photomixing in a low-temperature-grown GaAs photoconductor using a metallic mirror-based Fabry-Pérot cavity thanks to an impedance matching circuit.
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...
Low phase noise and tunable THz-signals from 300 GHz to 1 THz are obtained with a combination of a unitravelling carrier photodiode and a solid-state dual-frequency laser at 1.5 µm. The spectral purity is precisely characterized. Phase noises as low as −20 dBc/Hz at 1 kHz offset from the carrier frequency and an Allan deviation of 3·10−5 on 100 s are obtained.
A novel transition has been conceived from microstrip (MS) to rectangular metallic waveguide (WG) with good matching over a broad band. Electromagnetic (EM) simulations confirm these properties and the actual fabrication has been shown feasible. S-Parameters measurements are underway.
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