We present a photonically-excited antenna array at E-band for scanning by beam switching in wireless links. First, we discuss the proposed technique applied to photonic-enabled (sub)millimeter-wave ...transmitters. Next, we present our implementation; it consists of two sub-arrays of stacked patches as primary feeds of a Polytetrafluoroethylene (PTFE) lens, with one photodiode feeding each sub-array. To validate the assembly, the return loss and radiation patterns have been measured for one of the sub-arrays excited with a coplanar probe. In turn, the lens illuminated by one of the sub-arrays yields a directivity of 27 dBi. The radiation patterns measured for the transmitter module (including the lens) are in very good agreement with full-wave simulations, and they show that excitation of one of either sub-arrays allows beam switching between <inline-formula><tex-math notation="LaTeX">\pm 2.7^\circ</tex-math></inline-formula> with a beam crossover at <inline-formula><tex-math notation="LaTeX">-3\, \mathrm{dB}</tex-math></inline-formula>. Finally, we have tested the transmitter in a 0.6 m wireless link. Depending on the position of the detector and on which sub-array is excited, we have accomplished 5 Gbps transmission for on-off-keying modulation and direct detection (BER <inline-formula><tex-math notation="LaTeX">=10^{-11}</tex-math></inline-formula>). The system constitutes an initial proof of photonic-assisted beam switching for mm-wave transmitters enabling broadband operation with a directive and switchable beam.
We present a monolithically integrated mode-locked laser (MLL) with 25 GHz fundamental repetition rate frequency, which has been designed to operate in a fourth-order colliding regime, to generate ...100 GHz. This device has been fabricated within a multi-project wafer (MPW) run in an InP-based active-passive generic foundry. The Fabry-Perot laser resonator, of around 1.66 mm length, is defined by two on-chip reflectors, eliminating the need of cleaved facet. Three saturable absorber sections are symmetrically located by spacing them a quarter of this total length, dividing the cavity into four gain segments. We show that this structure can generate an electrical beat note at 25 GHz as well as 100 GHz, with a linewidth of 350 kHz and 150 kHz, respectively, operating in passive operation regime.
This manuscript reports the first leaky-wave antenna (LWA) array excited by a photomixer as well as its potential application for alignment in wireless links. The designed array is manufactured in ...printed circuit board (PCB) technology, works at the E-band (from 75 to 85 GHz), and provides a directive beam of about 18 dBi with a frequency scanning span of 22°. The antenna element consists of a microstrip line periodically loaded with stubs, and it has been designed employing a hybrid approach combining full-wave simulations and transmission line theory. This approach enables the optimization of the periods when the open-stopband of the LWA is mitigated or removed at the frequency of broadside emission. The proposed antenna was first tested using a ground signal ground (GSG) probe; the measured return loss and radiation patterns of the fabricated prototype were in good agreement with full-wave simulations. Then, the LWA array was integrated with the photomixer chip using conductive epoxy threads. Measurements of the radiated power yielded a maximum of 120 µW at 80.5 GHz for a 9.8 mA photocurrent. Finally, the antenna was used in a 25 cm wireless link, obtaining a 2.15 Gbps error-free data rate.
Se presentan los avances realizados en el desarrollo de generadores de peines de frecuencias ópticas (OFCG, Optical Frequency Comb Generator) mediante circuitos integrados fotónicos (PIC, Photonic ...Integrated Circuits). Estos son diseñados y fabricados en un proceso de oblea multi-proyecto de una plataforma genérica de integración. Se muestran los resultados experimentales de las diferentes clases de OFCG destacando los anchos de banda logrados, en el orden de THz. Se resalta la factibilidad de disponer circuitos fotónicos miniaturizados en sistemas de banda ancha y otras aplicaciones futuras en el marco de la nanotecnología.
Optoacoustic imaging (OAI) is an emerging biomedical technique that allows visualization of in-depth tissues by using ultrasonic signals generated by short laser pulses. In this work, the authors ...combine the optical power of several pulsed high-power diode lasers (HPDLs) at 870 nm and 905 nm to a 7-to-1 675-microm fiber bundle to generate optoacoustic (OA) signals from different mixtures of two gold nanorods solutions with absorbance peak at ~ 860 nm and ~ 900 nm, respectively. The pulses produced to generate OA signals are alternated between the two wavelengths by a microcontroller circuit with fast switching (0.5 ms). From the amplitude of the OA signals, the concentrations of the nanoparticles solutions are easily estimated with high accuracy using a fluence model. The results achieved with the proposed system show very good agreement between the concentrations of gold nanorods estimated from measurements and the expected values.
This manuscript reports the first leaky-wave antenna (LWA) array excited by a photomixer as well as its potential application for alignment in wireless links. The designed array is manufactured in ...printed circuit board (PCB) technology, works at the E-band (from 75 to 85 GHz), and provides a directive beam of about 18 dBi with a frequency scanning span of 22degrees. The antenna element consists of a microstrip line periodically loaded with stubs, and it has been designed employing a hybrid approach combining full-wave simulations and transmission line theory. This approach enables the optimization of the periods when the open-stopband of the LWA is mitigated or removed at the frequency of broadside emission. The proposed antenna was first tested using a ground signal ground (GSG) probe; the measured return loss and radiation patterns of the fabricated prototype were in good agreement with full-wave simulations. Then, the LWA array was integrated with the photomixer chip using conductive epoxy threads. Measurements of the radiated power yielded a maximum of 120 qW at 80.5 GHz for a 9.8 mA photocurrent. Finally, the antenna was used in a 25 cm wireless link, obtaining a 2.15 Gbps error-free data rate. Keywords: photomixer; photonic antenna; PCB antenna; E-band; beam scanning; beam steering; probe de-embedding; leaky-wave antenna; epoxy bonding; RF choke
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