Caracterización y Simulación de un Diodo Schottky de Microondas

Presentado en el XXVIII Simposium Nacional de la Unión Científica Internacional de Radio. URSI 2013, Santiago de Compostela, 11 al 13 de septiembre de 2013.Microwave diode models included in commercial simulators use a large set of parameters, so they are often difficult to set up in order to match the actual response of a specific device. In this paper a simple model for a zero-bias microwave Schottky diode is presented. Noise characteristics are determined by measurements and then incorporated to the large signal model offered by the manufacturer in the diode datasheet. Using this model a diode power detector in large signal operation is simulated with commercial software, achieving excellent agreement with the measurement results, both in terms of power sensitivity and noise spectrum.Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía, mediante el proyecto P09-TIC-5268. Universidad de Málaga - Campus de Excelencia Internacional Andalucía Tec

Six-Port-Based Architecture for Phase NoiseMeasurement in the UWB Band

A six-port-based frequency discriminator for phase noise measurement is proposed. This circuit makes use of a delay line discriminator configuration, thus not requiring reference oscillator. Furthermore, the use of a six-port network allows an extremely simple and completely passive solution well suited for low power oscillator measurement. A detailed study of the architecture is performed including the system noise sources. Besides, a prototype of the proposed six-port based delay line frequency discriminator is evaluated. Phase noise measurements of a commercial RF VCO are performed and compared with the results obtained with commercial metrology equipment with good agreement

Polarization and wavelength agnostic nanophotonic beam splitter

High-performance optical beam splitters are of fundamental importance for the development of advanced silicon photonics integrated circuits. However, due to the high refractive index contrast of the silicon-on-insulator platform, state of the art Si splitters are hampered by trade-offs in bandwidth, polarization dependence and sensitivity to fabrication errors. Here, we present a new strategy that exploits modal engineering in slotted waveguides to overcome these limitations, enabling ultra-wideband polarization-insensitive optical power splitters, with relaxed fabrication tolerances. The proposed splitter relies on a single-mode slot waveguide which is transformed into two strip waveguides by a symmetric taper, yielding equal power splitting. Based on this concept, we experimentally demonstrate -3$\pm$0.5 dB polarization-independent transmission in an unprecedented 390 nm bandwidth (1260 - 1650 nm), even in the presence of waveguide width deviations as large as $\pm$25 nm

Frequency locked loop architecture for phase noise reduction in wideband low-noise microwave oscillators.

Política de acceso abierto tomada de: https://digital-library.theiet.org/files/Author_self-archiving_policy.pdfA frequency locked loop (FLL) for phase noise reduction of wideband voltage controlled oscillators is proposed. The key building block of the system is a low noise (−160 dBV/Hz) and high sensitivity (22 V/GHz) delay line frequency discriminator with 5–8 GHz coverage, which makes use of a high performance multilayer hybrid. The authors derive closed-form, universal design equations for the maximum noise reduction and stability of the FLL circuitry. Application of the proposed technique to a state-of-the-art voltage controlled oscillator operating in the 5–8 GHz band yields a phase noise reduction of 8–10 dB at 100 kHz and 5 dB at 1 MHz off the carrier, which shows the results are in good agreement with the simulated results; so phase noise better than −107 dBc/Hz at 100 kHz and better than −123.5 dBc/Hz at 1 MHz is obtained

Butler Matrix Based Six-port Passive Junction

In this work we propose the utilization of the Butler matrix as a six-port I/Q demodulator. The inherent symmetry of its topology allows to overcome the intrinsic amplitude and phase imbalances of the traditional approaches making it more suitable for the design of high performance six-port networks. To demonstrate the validity of the proposal a Butler matrix has been designed covering the complete UWB band and its results are compared with the traditional approaches

Caracterización y Simulación de un Diodo Schottky de Microondas

Presentado en el XXVIII Simposium Nacional de la Unión Científica Internacional de Radio. URSI 2013, Santiago de Compostela, 11 al 13 de septiembre de 2013.Microwave diode models included in commercial simulators use a large set of parameters, so they are often difficult to set up in order to match the actual response of a specific device. In this paper a simple model for a zero-bias microwave Schottky diode is presented. Noise characteristics are determined by measurements and then incorporated to the large signal model offered by the manufacturer in the diode datasheet. Using this model a diode power detector in large signal operation is simulated with commercial software, achieving excellent agreement with the measurement results, both in terms of power sensitivity and noise spectrum.Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía, mediante el proyecto P09-TIC-5268. Universidad de Málaga - Campus de Excelencia Internacional Andalucía Tec

A chip-scale second-harmonic source via self-injection-locked all-optical poling

Abstract Second-harmonic generation allows for coherently bridging distant regions of the optical spectrum, with applications ranging from laser technology to self-referencing of frequency combs. However, accessing the nonlinear response of a medium typically requires high-power bulk sources, specific nonlinear crystals, and complex optical setups, hindering the path toward large-scale integration. Here we address all of these issues by engineering a chip-scale second-harmonic (SH) source based on the frequency doubling of a semiconductor laser self-injection-locked to a silicon nitride microresonator. The injection-locking mechanism, combined with a high-Q microresonator, results in an ultra-narrow intrinsic linewidth at the fundamental harmonic frequency as small as 41 Hz. Owing to the extreme resonant field enhancement, quasi-phase-matched second-order nonlinearity is photoinduced through the coherent photogalvanic effect and the high coherence is mapped on the generated SH field. We show how such optical poling technique can be engineered to provide efficient SH generation across the whole C and L telecom bands, in a reconfigurable fashion, overcoming the need for poling electrodes. Our device operates with milliwatt-level pumping and outputs SH power exceeding 2 mW, for an efficiency as high as 280%/W under electrical driving. Our findings suggest that standalone, highly-coherent, and efficient SH sources can be integrated in current silicon nitride photonics, unlocking the potential of χ (2) processes in the next generation of integrated photonic devices

Enhanced carbon nanotubes light emission integrated with photonic SOI ring resonators

International audienceWe present our recent results towards the integration of carbon nanotubes onto the SOI platform for the implementation of light sources. We experimentally demonstrate two-orders of magnitude enhancement of semiconductor single walled carbon nanotubes emission in fully integrated silicon microresonators

Butler Matrix Based Six-port Passive Junction

In this work we propose the utilization of the Butler matrix as a six-port I/Q demodulator. The inherent symmetry of its topology allows to overcome the intrinsic amplitude and phase imbalances of the traditional approaches making it more suitable for the design of high performance six-port networks. To demonstrate the validity of the proposal a Butler matrix has been designed covering the complete UWB band and its results are compared with the traditional approaches

Hybrid integration of carbon nanotube emitters into silicon photonic nanoresonators (Conference Presentation)

International audienceResearch of integrated light sources into the silicon platform has been extremely active for the past decades. Solutions such as the integration of III / V materials and components on silicon have been developed in a context of pre-industrial research, devices and systems intending very close to the market applications. The germanium(-tin) route has also demonstrated remarkable breakthroughs. The rationales of this research are the realization of optical interconnects. In parallel with these approaches, another interesting research field is the integration of nano-emitters, with the perspective of the realization of classical light sources but also of single photon and photon pair sources, in particular for quantum-on-chip communications. In this context, we propose the use of carbon nanotubes (CNTs) for the integration into silicon photonics towards novel optoelectronic devices. Indeed, CNTs are nanomaterials of particular interest in photonics thanks to their fundamental optical properties including near-IR luminescence, Stark effect, Kerr effect and absorption. Here, we report on the study of the light emission coupling from CNTs into optical nanobeam cavities implemented on the SOI platform. A wide range of situations have been studied by varying the deposition conditions of CNT-doped PFO polymer layers but also by considering different possible geometries of nanobeam cavities. Under optical pumping, we observe a very efficient coupling of the photoluminescence of the nanotubes with the modes of the nanocavities as well as a spectral narrowing of the photoluminescence spectra as a function of the optical power of the pump. These results contribute to the future realization of CNTs lasers, single photon and photon pair sources integrated on silicon. The authors thank the support of the European Commission's FP7-Cartoon project