High performace silicon 2x2 optical switch based on a thermo-optically tunable multimode interference coupler and efficient electrodes

Optical switches based on tunable multimode interference (MMI) couplers can simultaneously reduce the footprint and increase the tolerance against fabrication deviations. Here, a compact 2x2 silicon switch based on a thermo-optically tunable MMI structure with a footprint of only 0.005mm2 is proposed and demonstrated. The MMI structure has been optimized using a silica trench acting as a thermal isolator without introducing any substantial loss penalty or crosstalk degradation. Furthermore, the electrodes performance have significantly been improved via engineering the heater geometry and using two metallization steps. Thereby, a drastic power consumption reduction of around 90% has been demonstrated yielding to values as low as 24.9 mW. Furthermore, very fast switching times of only 1.19 μs have also been achieved.Financial support from LEOMIS TEC2012-38540 and PROMETEOII/2014/034 projects is acknowledged. Alvaro Rosa also acknowledges the Spanish Ministry of Economy and Competitiveness for funding his grant. The authors also would like to thank the Electronic Microscopy Department at UPV for taking the SEM images.Rosa Escutia, Á.; Gutiérrez Campo, AM.; Brimont, ACJ.; Griol Barres, A.; Sanchis Kilders, P. (2016). High performace silicon 2x2 optical switch based on a thermo-optically tunable multimode interference coupler and efficient electrodes. Optics Express. 24(1):191-198. https://doi.org/10.1364/OE.24.000191S191198241Subbaraman, H., Xu, X., Hosseini, A., Zhang, X., Zhang, Y., Kwong, D., & Chen, R. T. (2015). Recent advances in silicon-based passive and active optical interconnects. Optics Express, 23(3), 2487. doi:10.1364/oe.23.002487Nikolova, D., Rumley, S., Calhoun, D., Li, Q., Hendry, R., Samadi, P., & Bergman, K. (2015). Scaling silicon photonic switch fabrics for data center interconnection networks. Optics Express, 23(2), 1159. doi:10.1364/oe.23.001159Dong, P., Preble, S. 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Low-power, 2×2 silicon electro-optic switch with 110-nm bandwidth for broadband reconfigurable optical networks. Optics Express, 17(26), 24020. doi:10.1364/oe.17.024020Dong, P., Liao, S., Liang, H., Shafiiha, R., Feng, D., Li, G., … Asghari, M. (2010). Submilliwatt, ultrafast and broadband electro-optic silicon switches. Optics Express, 18(24), 25225. doi:10.1364/oe.18.025225Sun, P., & Reano, R. M. (2010). Submilliwatt thermo-optic switches using free-standing silicon-on-insulator strip waveguides. Optics Express, 18(8), 8406. doi:10.1364/oe.18.008406Watts, M. R., Sun, J., DeRose, C., Trotter, D. C., Young, R. W., & Nielson, G. N. (2013). Adiabatic thermo-optic Mach–Zehnder switch. Optics Letters, 38(5), 733. doi:10.1364/ol.38.000733Harris, N. C., Ma, Y., Mower, J., Baehr-Jones, T., Englund, D., Hochberg, M., & Galland, C. (2014). Efficient, compact and low loss thermo-optic phase shifter in silicon. Optics Express, 22(9), 10487. doi:10.1364/oe.22.010487Suzuki, K., Cong, G., Tanizawa, K., Kim, S.-H., Ikeda, K., Namiki, S., & Kawashima, H. (2015). Ultra-high-extinction-ratio 2 × 2 silicon optical switch with variable splitter. Optics Express, 23(7), 9086. doi:10.1364/oe.23.009086Sanchez, L., Griol, A., Lechago, S., Brimont, A., & Sanchis, P. (2015). Low-Power Operation in a Silicon Switch Based on an Asymmetric Mach–Zehnder Interferometer. IEEE Photonics Journal, 7(2), 1-8. doi:10.1109/jphot.2015.2407317Besse, P. A., Bachmann, M., Melchior, H., Soldano, L. B., & Smit, M. K. (1994). Optical bandwidth and fabrication tolerances of multimode interference couplers. Journal of Lightwave Technology, 12(6), 1004-1009. doi:10.1109/50.296191Soldano, L. B., & Pennings, E. C. M. (1995). Optical multi-mode interference devices based on self-imaging: principles and applications. Journal of Lightwave Technology, 13(4), 615-627. doi:10.1109/50.372474Leuthold, J., & Joyner, C. W. (2001). Multimode interference couplers with tunable power splitting ratios. Journal of Lightwave Technology, 19(5), 700-707. doi:10.1109/50.923483Fan Wang, Jianyi Yang, Limei Chen, Xiaoqing Jiang, & Minghua Wang. (2006). Optical switch based on multimode interference coupler. IEEE Photonics Technology Letters, 18(2), 421-423. doi:10.1109/lpt.2005.86320

Development, Demonstration, and Device Physics of FET-Accessed One-Transistor GaAs Dynamic Memory Technologies

The introduction of digital GaAs into modem high-speed computing systems has led to an increasing demand for high-density memory in these GaAs technologies. To date, most of the memory development efforts in GaAs have been directed toward four- and six-transistor static RAM\u27s, which consume substantial chip area and dissipate much static power resulting in limited single-chip GaAs storage capacities. As it has successfully done in silicon, a one-transistor dynamic RAM approach could alleviate these problems making higher density GaAs memories possible. This dissertation discusses theoretical and experimental work that presents the possibility for a high-speed, low-power, one-transistor dynamic RAM technology in GaAs. The two elements of the DRAM cell, namely the charge storage capacitor and the access field-effect transistor have been studied in detail. Isolated diode junction charge storage capacitors have demonstrated 30 minutes of storage time at room temperature with charge densities comparable to those obtained in planar silicon DRAM capacitors. GaAs JFET and MESFET technologies have been studied, and with careful device design and choice of proper operating voltages experimental results show that both can function as acceptable access transistors. One-transistor MESFET- and JFET-accessed DRAM cells have been fabricated and operated at room temperature and above with a standby power dissipation that is only a small fraction of the power dissipated by the best commercial GaAs static RAM cells. A 2 x 2 bit demonstration array was built and successfully operated at room temperature to demonstrate the addressable read/write capability of this new technology

A review of advances in pixel detectors for experiments with high rate and radiation

The Large Hadron Collider (LHC) experiments ATLAS and CMS have established hybrid pixel detectors as the instrument of choice for particle tracking and vertexing in high rate and radiation environments, as they operate close to the LHC interaction points. With the High Luminosity-LHC upgrade now in sight, for which the tracking detectors will be completely replaced, new generations of pixel detectors are being devised. They have to address enormous challenges in terms of data throughput and radiation levels, ionizing and non-ionizing, that harm the sensing and readout parts of pixel detectors alike. Advances in microelectronics and microprocessing technologies now enable large scale detector designs with unprecedented performance in measurement precision (space and time), radiation hard sensors and readout chips, hybridization techniques, lightweight supports, and fully monolithic approaches to meet these challenges. This paper reviews the world-wide effort on these developments.Comment: 84 pages with 46 figures. Review article.For submission to Rep. Prog. Phy

Silicon-on-insulator-based complementary metal oxide semiconductor integrated optoelectronic platform for biomedical applications

Microscale optical devices enabled by wireless power harvesting and telemetry facilitate manipulation and testing of localized biological environments (e.g., neural recording and stimulation, targeted delivery to cancer cells). Design of integrated microsystems utilizing optical power harvesting and telemetry will enable complex in vivo applications like actuating a single nerve, without the difficult requirement of extreme optical focusing or use of nanoparticles. Silicon-on-insulator (SOI)-based platforms provide a very powerful architecture for such miniaturized platforms as these can be used to fabricate both optoelectronic and microelectronic devices on the same substrate. Near-infrared biomedical optics can be effectively utilized for optical power harvesting to generate optimal results compared with other methods (e.g., RF and acoustic) at submillimeter size scales intended for such designs. We present design and integration techniques of optical power harvesting structures with complementary metal oxide semiconductor platforms using SOI technologies along with monolithically integrated electronics. Such platforms can become the basis of optoelectronic biomedical systems including implants and lab-on-chip systems

Hybrid Integrated Photonic Platforms and Devices

Integrated photonics has the potential to revolutionize optical systems by achieving drastic reductions in their size, weight and power. Remote spectroscopy, free-space communications and high-speed telecommunications are critical applications that would benefit directly from these advancements. However, many such applications require extremely wide spectral bandwidths, leading to significant challenges in their integration. The choice of integrated platform influences the optical transparency and functionality which can be ultimately achieved. In this work, several new platforms and technologies have been developed to meet these needs. First, the silicon-on-lithium-niobate (SiLN) platform is discussed, on which the first compact, integrated electro-optic modulator in the mid-infrared has been demonstrated. Next, results are shown in the development of the all-silicon-optical-platform (ASOP), an ultra-stable suspended membrane approach which offers broad optical transparency from 1.2 to 8.5 um and enables efficient nonlinear frequency conversion in the mid-IR. This fabrication approach is then taken further with anchored-membrane waveguides, (T-Guides) enabling single-mode and single-polarization waveguiding over a span exceeding 1.27 octaves. Afterward, a new photonic technology enabling integrated polarization beam-splitters and polarizers over unprecedented bandwidths is introduced, called topographically anisotropic photonics (TAP). Next, results on high-performance microphotonic chalcogenide glass waveguides are presented. Finally, several integrated photonics concepts suitable for further work will be discussed, such as augmentations to T-Guides and a novel technique for quasi-phase-matching

Development of High-Speed Silicon Devices and Their Design with Advanced Physical Models

In the field of high-speed silicon devices, silicon bipolar junction transistors (BJTs) had played a major role from the 1970s to the end of the 1980s. However, in the 1990s complementary metal-oxide-semiconductor (CMOS) .field effect transistors (FETs) have been replacing their position. This dissertation explains the reasons why BJTs were suitable for high-speed operation. This is concluded from the development of technologies for BJTs and the analyses of devices fabricated with these technologies. At the same time it clarifies why they were replaced by CMOS transistors. The BJT's high driving capability and large power dissipation were the both sides of a sword. In the case of high-speed CMOS devices, the driving current of MOSFET should be large enough, and device design must be based on precise comprehension of carrier transport in MOSFETs. Therefore, we need accurate device model as well as rigid device-structure information obtained by experiments. This dissertation describes the device design methodology not only based on inverse modeling to extract device structures consistent with all kinds of experimental results but also based on simulations by generalized hydrodynamic model and full-band Monte Carlo model. The background and concept of the methodology is also discussed, and its necessity in future development is clarified. Moreover, hot carrier modeling is discussed by employing full-band Monte Carlo device simulation. Also, this dissertation clarifies the fact there is no experimental evidence for the difference between the surface and bulk impact ionization mechanism in silicon. The reported difference in the literature was only caused by an unsound application of the local field model and was just an artifact. Finally, by using these sophisticated models, the saturation drain current as well as hot carrier effects of subquarter micron MOSFETs are analyzed. MOSFET design strategy for the 0.1 μ　m regime is discussed and the importance of shallow junction for source/drain extension is also clarified.広島大学(Hiroshima University)博士(工学)doctora

Quantum Cascade Laser Absorption Spectroscopy as a Plasma Diagnostic Tool: An Overview

The recent availability of thermoelectrically cooled pulsed and continuous wave quantum and inter-band cascade lasers in the mid-infrared spectral region has led to significant improvements and new developments in chemical sensing techniques using in-situ laser absorption spectroscopy for plasma diagnostic purposes. The aim of this article is therefore two-fold: (i) to summarize the challenges which arise in the application of quantum cascade lasers in such environments, and, (ii) to provide an overview of recent spectroscopic results (encompassing cavity enhanced methods) obtained in different kinds of plasma used in both research and industry

Integrated Spectroscopic Sensor fabricated in a novel Si3N4 platform

[ES] Esta tesis se ha centrado en el modelado, diseño y demostración experimental de un sensor espectroscópico integrado basado en un AWG (del inglés Arrayed Waveguide Grating). El dispositivo ha sido diseñado y fabricado en una nueva plataforma de nitruro de silico (Si3N4) en oxido de silico (SiO2) desarrollada en España. El trabajo realizado en esta tesis se puede dividir en dos secciones principalmente. En la primera parte, se describe el panorama general de las plataformas de Si3N4 existentes y su estado del arte, junto con la descripción de los procesos de fabricación y caracterización de nuestra plataforma de Si3N4 con 300 nm de altura en la capa de guiado. En la segunda parte, se presenta el dispositivo bautizado como Integrated Optical Spectroscopic Sensor (IOSS). El IOSS consiste en un AWG cuyo conjunto de guías de onda está dividido en dos subgupos diseñados para replicar los canales del AWG. Las guías de uno de los subgrupos contienen ventanas de sensado, que están definidas por secciones en las que el núcleo de las guías está al descubierto y, por tanto, en contacto con el medio que las rodea. De esta manera, el sensado se lleva a cabo mediante la interacción del campo evanescente con la muestra depositada. Las guías del segundo subconjunto permanecen inalteradas. Por lo tanto, el dispositivo proporciona al mismo tiempo los espectros de sensado y de referencia. El modelo matemático del IOSS, su procedimiento de diseño y la prueba de concepto del sensor configurado para espectroscopía de absorción se describen en esta tesis.[CAT] La present tesi s'ha centrat en el modelatge, disseny i demostració experimental d'un sensor espectroscòpic integrat basat en un AWG (de l'anglès Arrayed Waveguide Grating). El dispositiu ha sigut dissenyat i fabricat en una nova plataforma de nitrur de silici (Si3N4) en òxid de silici (SiO2) desenvolupada a Espanya. El treball realitzat en aquesta tesi es pot dividir en dues seccions principalment. En la primera part, es descriu el panorama general de les plataformes de Si3N4 existents i el seu estat de l'art, juntament amb la descripció dels processos de fabricació i caracterització de la nostra plataforma de Si3N4 amb 300 nm d'altura en la capa de guiat. En la segona part, es presenta el dispositiu batejat com Integrated Optical Spectroscopic Sensor (IOSS). El IOSS consisteix en un AWG en el que el seu conjunt de guies d'ona està dividit en dos subgrups dissenyats per a replicar els canals del AWG. Les guies d'un dels subgrups conté finestres de detecció, que estan definides per seccions en les quals el nucli de les guies d'ona està al descobert i en contacte amb el mitjà que li envolta. D'aquesta manera, la detecció es duu a terme mitjançant la interacció del camp evanescent amb la mostra depositada. Les guies del segon subconjunt romanen inalterades. Per tant, el dispositiu proporciona al mateix temps els espectres de detecció de referència. El model matemàtic del IOSS, el seu procediment de disseny i la prova de concepte del sensor configurat per a espectroscopia d'absorció es descriuen en aquesta tesi.[EN] This thesis is focused on the model, design and experimental demonstration of an integrated spectroscopic sensor based on a modified Arrayed Waveguide Grating (AWG). The device has been designed and fabricated in a new silicon nitride (Si3N4) on silicon oxide (SiO2) platform developed in Spain. The work performed for this thesis can be then divided into two main sections. In the first part, an overview of the existing Si3N4 platforms and their state of art is described, alongside the report on the fabrication and characterization of our 300 nm guiding film height Si3N4 platform. On the second part, the device named Integrated Optical Spectroscopic Sensor (IOSS) is presented. The IOSS consists of an AWG which arrayed waveguides are divided into two sub-sets engineered to replicate the AWG channels. The waveguides of one of the sub-sets contain sensing windows, defined as waveguides sections which core is in contact with the surrounding media. Thus, the sensing is performed through evanescent field interaction with the sample deposited. The waveguides from the second sub-set remain isolated. Therefore, the device provides both sensing and reference spectra. The IOSS mathematical model, design procedure and proof of concept configured for absorption spectroscopy are reported in this thesis.Micó Cabanes, G. (2020). Integrated Spectroscopic Sensor fabricated in a novel Si3N4 platform [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159381TESI

Liquid metals as a divertor plasma facing material explored using the Pilot-PSI and Magnum-PSI linear devices

Abstract For DEMO and beyond liquid metal plasma facing components are considered due to their resilience to erosion through flowed replacement, potential for cooling beyond conduction and inherent immunity to many of the issues of neutron loading compared to solid materials. The development curve of liquid metals is behind that of e.g. tungsten however and tokamak-based research is currently somewhat limited in scope. Therefore investigation in linear plasma devices can provide faster progress under controlled and well-diagnosed conditions in assessing many of the issues surrounding the use of liquid metals. The linear plasma devices Magnum-PSI and Pilot-PSI are capable of producing DEMO relevant plasma fluxes which well replicate expected divertor conditions, and the exploration of physics issues for tin (Sn) and lithium (Li) such as vapour-shielding, erosion under high particle flux loading and overall power handing are reviewed here. A deeper understanding of erosion and deposition through this work indicates that stannane formation may play an important role in enhancing Sn erosion, while on the other hand the strong hydrogen isotope affinity reduces the evaporation rate and sputtering yields for Li. In combination with the strong re-deposition rates which have been observed under this type of high density plasma this implies an increase in the operational temperature range, implying a power handling range of 20-25 MW m -2 for Sn and up to 12.5 MW m -2 for Li could be achieved. Vapour shielding may be expected to act as a self-protection mechanism in reducing the heat load to the substrate for off-normal events in the case of Sn, but may potentially be a continual mode of operation for Li.</p