scholarly journals Analysis of Quality Factor Enhancement in the Monolithic InGaN/GaN Nanorod Array

2019 ◽  
Vol 9 (7) ◽  
pp. 1295
Author(s):  
Chia-Yen Huang ◽  
Tzu-Ying Tai ◽  
Kuo-Bin Hong ◽  
Hao-Chung Kuo ◽  
Tien-Chang Lu
Keyword(s):  
Integrated Circuits ◽  
Quality Factor ◽  
Mode Selection ◽  
Building Blocks ◽  
Nanorod Array ◽  
Dominant Mode ◽  
Scattering Loss ◽  
Whispering Gallery ◽  
Rod Array ◽  
Good Agreement

Whispering gallery mode (WGM) lasers and resonators are key building blocks for photonic integrated circuits. The quality factor and resonant wavelength are strong functions of the cavity size. Nanoscale WGM cavities suffer from a low-quality factor due to prominent scattering loss. However, the quality factor could be enhanced by forming an optically-coupled rod array or photonic molecules. Through simulations, we revealed how rod-to-rod optical coupling influenced the threshold pumping level and dominant mode selection, where the trend showed good agreement with the experimental observation. According to the simulation, the quality factor could be enhanced by up to eight times by forming a six-rod photonic molecule. The quality factor and effective mode were both superior to the single rods with the same wafer device footprint.

scholarly journals Coherent suppression of backscattering in optical microresonators

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Andreas Ø. Svela ◽  
Jonathan M. Silver ◽  
Leonardo Del Bino ◽  
Shuangyou Zhang ◽  
Michael T. M. Woodley ◽  
...  
Keyword(s):  
Quality Factor ◽  
Bulk Material ◽  
Near Field ◽  
High Quality Factor ◽  
Dual Frequency ◽  
High Quality ◽  
Frequency Combs ◽  
Optical Microresonators ◽  
Whispering Gallery ◽  
The Stability

AbstractAs light propagates along a waveguide, a fraction of the field can be reflected by Rayleigh scatterers. In high-quality-factor whispering-gallery-mode microresonators, this intrinsic backscattering is primarily caused by either surface or bulk material imperfections. For several types of microresonator-based experiments and applications, minimal backscattering in the cavity is of critical importance, and thus, the ability to suppress backscattering is essential. We demonstrate that the introduction of an additional scatterer into the near field of a high-quality-factor microresonator can coherently suppress the amount of backscattering in the microresonator by more than 30 dB. The method relies on controlling the scatterer position such that the intrinsic and scatterer-induced backpropagating fields destructively interfere. This technique is useful in microresonator applications where backscattering is currently limiting the performance of devices, such as ring-laser gyroscopes and dual frequency combs, which both suffer from injection locking. Moreover, these findings are of interest for integrated photonic circuits in which back reflections could negatively impact the stability of laser sources or other components.

scholarly journals Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1286
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak
Keyword(s):  
Integrated Circuits ◽  
Optical Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Junction Temperature ◽  
Optical Parameters ◽  
Spice Simulation ◽  
Light Emitting ◽  
Proposed Model ◽  
Good Agreement

This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was performed for the investigated diodes operating alone and together. Good agreement between the results of measurements and computations was obtained. It was also proved that the main thermal and optical parameters of the investigated LEDs depend on a dominant wavelength of the emitted light.

scholarly journals Design of an Ultra-Low Voltage Bias Current Generator Highly Immune to Electromagnetic Interference

2021 ◽  
Vol 11 (1) ◽  
pp. 6
Author(s):  
Orazio Aiello
Keyword(s):  
Integrated Circuits ◽  
Electromagnetic Interference ◽  
Low Voltage ◽  
Current Source ◽  
Building Blocks ◽  
Cmos Technology ◽  
Threshold Region ◽  
Output Current ◽  
Current Generator ◽  
Technology Process

The paper deals with the immunity to Electromagnetic Interference (EMI) of the current source for Ultra-Low-Voltage Integrated Circuits (ICs). Based on the properties of IC building blocks, such as the current-splitter and current correlator, a novel current generator is conceived. The proposed solution is suitable to provide currents to ICs operating in the sub-threshold region even in the presence of an electromagnetic polluted environment. The immunity to EMI of the proposed solution is compared with that of a conventional current mirror and evaluated by analytic means and with reference to the 180 nm CMOS technology process. The analysis highlights how the proposed solution generates currents down to nano-ampere intrinsically robust to the Radio Frequency (RF) interference affecting the input of the current generator, differently to what happens to the output current of a conventional mirror under the same conditions.

scholarly journals Interband Cascade Photonic Integrated Circuits on Native III-V Chip

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 599
Author(s):  
Jerry R. Meyer ◽  
Chul Soo Kim ◽  
Mijin Kim ◽  
Chadwick L. Canedy ◽  
Charles D. Merritt ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Detection System ◽  
Laser Cavity ◽  
Building Blocks ◽  
Drive Power ◽  
Optical Elements ◽  
Photonic Integrated Circuit ◽  
Cleaved Facets ◽  
On Chip

We describe how a midwave infrared photonic integrated circuit (PIC) that combines lasers, detectors, passive waveguides, and other optical elements may be constructed on the native GaSb substrate of an interband cascade laser (ICL) structure. The active and passive building blocks may be used, for example, to fabricate an on-chip chemical detection system with a passive sensing waveguide that evanescently couples to an ambient sample gas. A variety of highly compact architectures are described, some of which incorporate both the sensing waveguide and detector into a laser cavity defined by two high-reflectivity cleaved facets. We also describe an edge-emitting laser configuration that optimizes stability by minimizing parasitic feedback from external optical elements, and which can potentially operate with lower drive power than any mid-IR laser now available. While ICL-based PICs processed on GaSb serve to illustrate the various configurations, many of the proposed concepts apply equally to quantum-cascade-laser (QCL)-based PICs processed on InP, and PICs that integrate III-V lasers and detectors on silicon. With mature processing, it should become possible to mass-produce hundreds of individual PICs on the same chip which, when singulated, will realize chemical sensing by an extremely compact and inexpensive package.

Passive Components for RF-ICs

2012 ◽  
pp. 189-214
Author(s):  
Gianluca Cornetta ◽  
David J. Santos ◽  
José Manuel Vázquez
Keyword(s):  
Integrated Circuits ◽  
Quality Factor ◽  
Silicon Substrate ◽  
Supply Voltage ◽  
Magnetic Behavior ◽  
Low Noise ◽  
Low Noise Amplifiers ◽  
Fully Integrated ◽  
Core Elements ◽  
Low Supply Voltage

The modern wireless communication industry is demanding transceivers with a high integration level operating in the gigahertz frequency range. This, in turn, has prompted intense research in the area of monolithic passive devices. Modern fabrication processes now provide the capability to integrate onto a silicon substrate inductors and capacitors, enabling a broad range of new applications. Inductors and capacitors are the core elements of many circuits, including low-noise amplifiers, power amplifiers, baluns, mixers, and oscillators, as well as fully-integrated matching networks. While the behavior and the modeling of integrated capacitors are well understood, the design of an integrated inductor is still a challenging task since its magnetic behavior is hard to predict accurately. As the operating frequency approaches the gigahertz range, device nonlinearities, coupling effects, and skin effect dominate, making difficult the design of critical parameters such as the self-resonant frequency, the quality factor, and self and mutual inductances. However, despite the parasitic effects and the low quality-factor, integrated inductors still allow for the implementation of integrated circuits with improved performances under low supply voltage. In this chapter, the authors review the technology behind monolithic capacitors and inductors on silicon substrate for high-frequency applications, with major emphasis on physical implementation and modeling.

scholarly journals Photonic Crystal Cavity with a Thin Low-Index Layer for Silicon-Compatible Nanolight Source

2018 ◽  
Vol 8 (9) ◽  
pp. 1552 ◽  
Author(s):  
Youngsoo Kim ◽  
Young Lee ◽  
Seokhyeon Hong ◽  
Kihwan Moon ◽  
Soon-Hong Kwon
Keyword(s):  
Photonic Crystal ◽  
Integrated Circuits ◽  
Quality Factor ◽  
Wavelength Region ◽  
High Quality Factor ◽  
Silica Layer ◽  
High Quality ◽  
Light Emitting ◽  
Telecommunication Wavelength ◽  
Silicon Based

The development of an efficient silicon-based nanolight source is an important step for silicon-based photonic integrated circuits. We propose a high quality factor photonic crystal nanocavity consisting of silicon and silica, which can be used as a silicon-compatible nanolight source. We show that this cavity can effectively confine lights in a low-index silica layer with a high confinement factor of 0.25, in which rare-earth dopants can be embedded as gain materials. The cavity is optimized to have a high quality factor of 15,000 and a mode volume of 0.01 μm3, while the resonance has a wavelength of 1537 nm. We expect that the high confinement factor in the thin silica layer and the high quality factor of the proposed cavity enable the cavity to be a good candidate for silicon-compatible nanolight sources for use in nanolasers or light-emitting diodes in the telecommunication wavelength region.

scholarly journals A Vibrometer Based on Magnetorheological Optical Resonators

Vibration ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 239-249 ◽  
Author(s):  
Edoardo Rubino ◽  
Tindaro Ioppolo
Keyword(s):  
Permanent Magnet ◽  
Quality Factor ◽  
Polyvinyl Chloride ◽  
Optical Quality ◽  
Optical Resonator ◽  
Experimental Results ◽  
Whispering Gallery Modes ◽  
Moving Surface ◽  
Whispering Gallery ◽  
Optical Modes

This paper addresses the feasibility of an optical vibrometer that is based on the shift of the optical modes, also known as whispering gallery modes (WGMs), of a magnetorheological optical resonator. The optical resonator that is used in this study is fabricated by mixing polyvinyl chloride plastisol with magnetically polarizable particles. When a permanent magnet that is located nearby the optical resonator is moved, it induces a perturbation of the morphology of the resonator, due to the magnetostrictive effect. This change in the morphology induces a shift in the optical modes of the resonator. The shift of the optical modes can be related to the displacement of the permanent magnet. The proposed sensor concept is based on monitoring the displacement of a tiny magnet that is attached to a moving surface. The optical quality factor of the resonator used in these studies was of the order of 106. The experimental results show a sensitivity of 0.32 pm/μm and a resolution that is less than 300 nm.

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