scholarly journals Analysis of Optical Integration between Si3N4 Waveguide and a Ge-Based Optical Modulator Using a Lateral Amorphous GeSi Taper at the Telecommunication Wavelength of 1.55 µm

2019 ◽  
Vol 9 (18) ◽  
pp. 3846
Author(s):  
Worawat Traiwattanapong ◽  
Kazumi Wada ◽  
Papichaya Chaisakul
Keyword(s):  
Low Voltage ◽  
Extinction Ratio ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Fdtd Simulation ◽  
Optical Modulator ◽  
Optical Modulators ◽  
Optical Wavelength ◽  
Mode Size ◽  
Small Footprint

We report on the theoretical investigation of using an amorphous Ge0.83Si0.17 lateral taper to enable a low-loss small-footprint optical coupling between a Si3N4 waveguide and a low-voltage Ge-based Franz–Keldysh optical modulator on a bulk Si substrate using 3D Finite-Difference Time-Domain (3D-FDTD) simulation at the optical wavelength of 1550 nm. Despite a large refractive index and optical mode size mismatch between Si3N4 and the Ge-based modulator, the coupling structure rendered a good coupling performance within fabrication tolerance of advanced complementary metal-oxide semiconductor (CMOS) processes. For integrated optical modulator performance, the Si3N4-waveguide-integrated Ge-based on Si optical modulators could simultaneously provide workable values of extinction ratio (ER) and insertion loss (IL) for optical interconnect applications with a compact footprint.

scholarly journals All-optical modulation based on MoS2-Plasmonic nanoslit hybrid structures

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Feiying Sun ◽  
Changbin Nie ◽  
Xingzhan Wei ◽  
Hu Mao ◽  
Yupeng Zhang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Single Layer ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Optical Modulator ◽  
Small Scale ◽  
Light Modulation ◽  
Optical Modulators ◽  
Signal Light ◽  
All Optical

Abstract Two-dimensional (2D) materials with excellent optical properties and complementary metal-oxide-semiconductor (CMOS) compatibility have promising application prospects for developing highly efficient, small-scale all-optical modulators. However, due to the weak nonlinear light-material interaction, high power density and large contact area are usually required, resulting in low light modulation efficiency. In addition, the use of such large-band-gap materials limits the modulation wavelength. In this study, we propose an all-optical modulator integrated Si waveguide and single-layer MoS2 with a plasmonic nanoslit, wherein modulation and signal light beams are converted into plasmon through nanoslit confinement and together are strongly coupled to 2D MoS2. This enables MoS2 to absorb signal light with photon energies less than the bandgap, thereby achieving high-efficiency amplitude modulation at 1550 nm. As a result, the modulation efficiency of the device is up to 0.41 dB μm−1, and the effective size is only 9.7 µm. Compared with other 2D material-based all-optical modulators, this fabricated device exhibits excellent light modulation efficiency with a micron-level size, which is potential in small-scale optical modulators and chip-integration applications. Moreover, the MoS2-plasmonic nanoslit modulator also provides an opportunity for TMDs in the application of infrared optoelectronics.

scholarly journals Investigation of PVT-Aware STT-MRAM Sensing Circuits for Low-VDD Scenario

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 551
Author(s):  
Zhongjian Bian ◽  
Xiaofeng Hong ◽  
Yanan Guo ◽  
Lirida Naviner ◽  
Wei Ge ◽  
...  
Keyword(s):  
Nonvolatile Memory ◽  
High Speed ◽  
Low Voltage ◽  
Supply Voltage ◽  
Random Access ◽  
Magnetic Tunnel Junction ◽  
Complementary Metal Oxide Semiconductor ◽  
Current Mode ◽  
Cmos Technology ◽  
Oxide Semiconductor

Spintronic based embedded magnetic random access memory (eMRAM) is becoming a foundry validated solution for the next-generation nonvolatile memory applications. The hybrid complementary metal-oxide-semiconductor (CMOS)/magnetic tunnel junction (MTJ) integration has been selected as a proper candidate for energy harvesting, area-constraint and energy-efficiency Internet of Things (IoT) systems-on-chips. Multi-VDD (low supply voltage) techniques were adopted to minimize energy dissipation in MRAM, at the cost of reduced writing/sensing speed and margin. Meanwhile, yield can be severely affected due to variations in process parameters. In this work, we conduct a thorough analysis of MRAM sensing margin and yield. We propose a current-mode sensing amplifier (CSA) named 1D high-sensing 1D margin, high 1D speed and 1D stability (HMSS-SA) with reconfigured reference path and pre-charge transistor. Process-voltage-temperature (PVT) aware analysis is performed based on an MTJ compact model and an industrial 28 nm CMOS technology, explicitly considering low-voltage (0.7 V), low tunneling magnetoresistance (TMR) (50%) and high temperature (85 °C) scenario as the worst sensing case. A case study takes a brief look at sensing circuits, which is applied to in-memory bit-wise computing. Simulation results indicate that the proposed high-sensing margin, high speed and stability sensing-sensing amplifier (HMSS-SA) achieves remarkable performance up to 2.5 GHz sensing frequency. At 0.65 V supply voltage, it can achieve 1 GHz operation frequency with only 0.3% failure rate.

scholarly journals 100 Gb/s Silicon Photonic WDM Transmitter with Misalignment-Tolerant Surface-Normal Optical Interfaces

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 336 ◽  
Author(s):  
Beiju Huang ◽  
Zanyun Zhang ◽  
Zan Zhang ◽  
Chuantong Cheng ◽  
Huang Zhang ◽  
...  
Keyword(s):  
Wavelength Division Multiplex ◽  
Complementary Metal Oxide Semiconductor ◽  
Silicon On Insulator ◽  
Oxide Semiconductor ◽  
Optical Modulator ◽  
Grating Coupler ◽  
Coupling Loss ◽  
Wavelength Division ◽  
Silicon Photonic ◽  
Fiber Misalignment

A 4 × 25 Gb/s ultrawide misalignment tolerance wavelength-division-multiplex (WDM) transmitter based on novel bidirectional vertical grating coupler has been demonstrated on complementary metal-oxide-semiconductor (CMOS)-compatible silicon-on-insulator (SOI) platform. Simulations indicate the bidirectional grating coupler (BGC) is widely misalignment tolerant, with an excess coupling loss of only 0.55 dB within ±3 μm fiber misalignment range. Measurement shows the excess coupling loss of the BGC is only 0.7 dB within a ±2 μm fiber misalignment range. The bidirectional grating structure not only functions as an optical coupler, but also acts as a beam splitter. By using the bidirectional grating coupler, the silicon optical modulator shows low insertion loss and large misalignment tolerance. The eye diagrams of the modulator at 25 Gb/s don’t show any obvious deterioration within the waveguide-direction fiber misalignment ranger of ±2 μm, and still open clearly when the misalignment offset is as large as ±4 μm.

Piezoelectric Thin Films for Sensors, Actuators, and Energy Harvesting

MRS Bulletin ◽  
2009 ◽  
Vol 34 (9) ◽  
pp. 658-664 ◽  
Author(s):  
P. Muralt ◽  
R. G. Polcawich ◽  
S. Trolier-McKinstry
Keyword(s):  
Thin Films ◽  
Energy Harvesting ◽  
Microelectromechanical Systems ◽  
Low Voltage ◽  
High Sensitivity ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Mems Devices ◽  
Si Substrates ◽  
The Impact

AbstractPiezoelectric microelectromechanical systems (MEMS) offer the opportunity for high-sensitivity sensors and large displacement, low-voltage actuators. In particular, recent advances in the deposition of perovskite thin films point to a generation of MEMS devices capable of large displacements at complementary metal oxide semiconductor-compatible voltage levels. Moreover, if the devices are mounted in mechanically noisy environments, they also can be used for energy harvesting. Key to all of these applications is the ability to obtain high piezoelectric coefficients and retain these coefficients throughout the microfabrication process. This article will review the impact of composition, orientation, and microstructure on the piezoelectric properties of perovskite thin films such as PbZr1−xTixO3 (PZT). Superior piezoelectric coefficients (e31, f of −18 C/m2) are achieved in {001}-oriented PbZr0.52Ti0.48O3 films with improved compositional homogeneity on Si substrates. The advent of such high piezoelectric responses in films opens up a wide variety of possible applications. A few examples of these, including low-voltage radio frequency MEMS switches and resonators, actuators for millimeter-scale robotics, droplet ejectors, energy scavengers for unattended sensors, and medical imaging transducers, will be discussed.

Realization of Fractional-Order Double-Scroll Chaotic System Using Operational Transconductance Amplifier (OTA)

2017 ◽  
Vol 27 (01) ◽  
pp. 1850006 ◽  
Author(s):  
Mohammad Rafiq Dar ◽  
Nasir Ali Kant ◽  
Farooq Ahmad Khanday
Keyword(s):  
Fractional Order ◽  
Chaotic System ◽  
Low Voltage ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Operational Transconductance Amplifiers ◽  
System A ◽  
Transconductance Amplifier ◽  
Theoretical Predictions

Realization of fractional-order double-scroll chaotic system using Operational Transconductance Amplifiers (OTAs) as active elements are presented in this paper. The fractional-order double-scroll chaotic system has been studied before as well using passive RC-ladder and tree-based structures but in this paper the requisite fractional-order integration has been accomplished through an integer-order multiple-feedback topology. As compared to double or multiple scroll chaotic systems existing in the open literature, the proposed realization offers the advantages of (a) low-voltage implementation, (b) integrablity as the design is resistor- and inductor-less and only grounded components have been employed in the design, and, (c) electronic tunability of the fractional order, time-constants and gain factors. In order to demonstrate the usefulness of the chaotic system, a simple secure message communication system has been designed and verified for its operation. The theoretical predictions of the proposed implementations have been verified by using 0.35[Formula: see text][Formula: see text]m complementary metal oxide semiconductor (CMOS) process file provided by Austrian Micro System (AMS).

scholarly journals Electro-Absorption Modulation in GeSn Alloys for Wide-Spectrum Mid-Infrared Applications

2021 ◽  
Author(s):  
Yun-Da Hsieh ◽  
Jun-Han Lin ◽  
Richard Soref ◽  
Greg Sun ◽  
Hung-Hsiang Cheng ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Wide Spectrum ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Optical Modulation ◽  
Bandgap Energy ◽  
Optical Modulators ◽  
Mid Infrared ◽  
Wide Range ◽  
On Chip

Abstract Si-based electronic-photonic integrated circuits (EPICs), which are compatible with state-of-the-art complementary metal-oxide-semiconductor (CMOS) processes, offer promising opportunities for on-chip mid-infrared (MIR) photonic systems. However, the lack of efficient MIR optical modulators on Si hinders the utilization of MIR EPICs. Here, we clearly demonstrate the Franz-Keldysh (FK) effect in GeSn alloys and achieve on-Si MIR electro-absorption optical modulation using GeSn heterostructures. Our experimental and theoretical results verify that the direct bandgap energy of GeSn can be widely tuned by varying the Sn content, thereby realizing wavelength-tunable optical modulation in the MIR range with a figure-of-merit of Δα /α0 (FOM) greater than 1.5 and a broadband operating range greater than 140 nm. In contrast to conventional silicon-photonic modulators based on the plasma dispersion effect, our GeSn heterostructure demonstrates practical and effective FK MIR optical modulation on Si and helps unlock the potential of MIR EPICs for a wide range of applications.

scholarly journals A Fully-Integrated 180 nm CMOS 1.2 V Low-Dropout Regulator for Low-Power Portable Applications

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2108
Author(s):  
Jorge Pérez-Bailón ◽  
Belén Calvo ◽  
Nicolás Medrano
Keyword(s):  
Low Voltage ◽  
Low Cost ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Technology ◽  
High Gain ◽  
Oxide Semiconductor ◽  
Fully Integrated ◽  
Low Voltage Operation ◽  
Error Amplifier ◽  
Ldo Regulator

This paper presents the design and postlayout simulation results of a capacitor-less low dropout (LDO) regulator fully integrated in a low-cost standard 180 nm Complementary Metal-Oxide-Semiconductor (CMOS) technology which regulates the output voltage at 1.2 V from a 3.3 to 1.3 V battery over a –40 to 120°C temperature range. To meet with the constraints of system-on-chip (SoC) battery-operated devices, ultralow power (Iq = 8.6 µA) and minimum area consumption (0.109 mm2) are maintained, including a reference voltage Vref = 0.4 V. It uses a high-gain dynamically biased folded-based error amplifier topology optimized for low-voltage operation that achieves an enhanced regulation-fast transient performance trade-off.

Sign in / Sign up

Export Citation Format

Share Document