Junction temperature measurement in optically-activated power MOSFET

2022 ◽  
Author(s):  
Sandro Rao ◽  
Elisa D Mallemace ◽  
Maurizio Casalino ◽  
Giuseppe Cocorullo ◽  
Lakhdar Dehimi ◽  
...  
Keyword(s):  
Refractive Index ◽  
Refractive Index Change ◽  
Optical Power ◽  
Junction Temperature ◽  
Essential Information ◽  
Power Mosfet ◽  
Practical Applications ◽  
Power Operations ◽  
Fabry Perot ◽  
Periodic Monitoring

Abstract The temperature-dependent optical properties of silicon carbide (SiC), such as refractive index and reflectivity, have been used for a direct monitoring of the junction temperature of a power MOSFET. In particular, the optical response of a 4H-SiC MOSFET-integrated Fabry-Perot cavity to temperature changes has been investigated through parametric optical simulations at the wavelength of λ=450 nm. The reflected optical power exhibited oscillatory patterns caused by the multiple beam interference for which the MOSFET epilayer, between the gate-oxide and the doped 4H-SiC substrate, acts as a Fabry-Perot etalon. These results were used to calculate the refractive index change and, therefore, the optical phase shift of ∆φ= π/2 corresponding to a temperature variation that can be considered as a warning for the device “health”. In practical applications, the periodic monitoring of the optic spectrum at the interferometric structure output gives an essential information about the device operating temperature condition that, for high power operations, may lead to device damages or system failure.

scholarly journals Significant photoinduced refractive index change observed in porous silicon Fabry–Pérot resonators

2000 ◽  
Vol 76 (15) ◽  
pp. 1990-1992 ◽  
Author(s):  
Morio Takahashi ◽  
Yuichi Toriumi ◽  
Takahiro Matsumoto ◽  
Yasuaki Masumoto ◽  
Nobuyoshi Koshida
Keyword(s):  
Refractive Index ◽  
Porous Silicon ◽  
Refractive Index Change ◽  
Index Change ◽  
Fabry Perot

scholarly journals Phenomenon of Electromagnetic Field Resonance in Metal and Dielectric Gratings and Its Possible Practical Applications

2020 ◽  
Vol 5 (3) ◽  
pp. 49
Author(s):  
Stefano Bellucci ◽  
Andrii Bendziak ◽  
Oleksandr Vernyhor ◽  
Volodymyr M. Fitio
Keyword(s):  
Refractive Index ◽  
Buffer Layer ◽  
Propagation Constant ◽  
Refractive Index Change ◽  
Dielectric Substrate ◽  
Angular Sensitivity ◽  
Practical Applications ◽  
Dielectric Gratings ◽  
Constant Change ◽  
Dielectric Grating

Calculations of the field distribution in the structure of the dielectric substrate/buffer layer/volume phase grating/analyzed medium were performed. It is shown that in the presence of a buffer layer with a low refractive index in the dielectric waveguide leads to a shift of the maximum field at the waveguide resonance into analyzed medium. As a result, the spectral and angular sensitivity of the corresponding sensor increases. Based on the waveguide equation, analytical expressions are obtained that connect the spectral and angular sensitivity of the sensor to the sensitivity of the propagation constant change due to the refractive index change of the analyzed medium. The conditions for the excitation of the resonance of surface plasmon–polariton waves in the structure with a metal or dielectric grating on a metal substrate are also given. The fields that occur at resonance for silver and gold gratings are calculated.

FABRICATION OF MACH-ZEHNDER INTERFEROMETOR BASED ON PLANAR WAVEGUIDE FOR THE APPLICATION OF BIOSENSORS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1891-1896 ◽  
Author(s):  
JUN-HYONG KIM ◽  
HOE-YOUNG YANG ◽  
HYUN-YONG LEE
Keyword(s):  
Refractive Index ◽  
Optical Waveguides ◽  
Planar Waveguide ◽  
Refractive Index Change ◽  
Optical Power ◽  
Input Power ◽  
Design Rule ◽  
Integrated Optical ◽  
The Difference ◽  
Planar Lightwave

In this paper, designed and simulated Power Splitter (PS) integrated Mach-Zehnder interferometer (MZI) based planar waveguide devices (which is called here a PS-MZI). Moreover, we fabricated optical waveguide based on the PS-MZI for application to the biosensor. The integrated optical structure is sensitive to refractive index change induced due to the interaction of the evanescent field with an immobilized biological sample placed on one of the two arms of the interferometer. The PS-MZI sensor was preceded by a Y -junction, which splits the input power between the sensor and a reference branch to minimize the effect of optical power variations. The waveguide were optimized at a wavelength of 1550 nm and fabricated according to the design rule of 0.45 delta%, which is the difference of refractive index between the core and clad. The fabrication of PS-MZI optical waveguides was performed by a conventional planar lightwave circuit (PLC) fabrication process. The PS-MZI optical waveguides were measured of the optical characteristics for the application of biosensors.

scholarly journals High-Sensitive TM Modes in Photonic Crystal Nanobeam Cavity with Horizontal Air Gap for Refractive Index Sensing

2019 ◽  
Vol 9 (5) ◽  
pp. 967 ◽  
Author(s):  
Jin-Kyu Yang ◽  
Chae-Young Kim ◽  
Minji Lee
Keyword(s):  
Refractive Index ◽  
Photonic Crystal ◽  
Refractive Index Change ◽  
Air Gap ◽  
Q Factor ◽  
Practical Applications ◽  
Refractive Index Sensing ◽  
Tm Mode ◽  
Cavity Structure ◽  
New Type

We propose a new type of refractive index sensing based on the transverse magnetic (TM) modes in the photonic crystal (PhC) nanobeam (NB) cavity with a horizontal air gap. The electric field of the resonant TM mode is strongly confined within the horizontal air gap present at the PhC NB cavity. In order to increase the quality (Q) factor and the sensitivity (S) of the refractive index change in the air simultaneously, the cavity structure is fully optimized. Because of the trade-off between the Q-factor and S of the TM mode in the PhC NB cavity with an air gap, there is an optimal thickness of the air gap in the dielectric slot. From the numerical simulation results, S can exceed 1000 nm/RIU with Q > 40,000. When the dielectric slot becomes thin, S could be higher than 1200 nm/RIU. For practical applications, we suggest an Si-based PhC NB cavity with a horizontal SiO2 slot structure which can also provide high S with a high Q-factor after a very fine selective wet etching process. This new type of TM resonant mode in the PhC NB cavity can be an ideal platform for compact sensors in photonic integrated circuits for TM waveguide systems.

Temperature-Insensitive Miniaturized Fiber Inline Fabry-Perot Interferometer Fabricated by Femtosecond Laser

2008 ◽  
Author(s):  
Yukun Han ◽  
Cheng-Hsiang Lin ◽  
Hai-Lung Tsai ◽  
Tao Wei ◽  
Hai Xiao
Keyword(s):  
Refractive Index ◽  
Refractive Index Change ◽  
High Sensitivity ◽  
Temperature Dependent ◽  
Refractive Index Measurement ◽  
Index Measurement ◽  
Highly Sensitive ◽  
Fabry Perot ◽  
Fs Laser ◽  
One Step

This article presents a miniaturized fiber inline Fabry-Perot interferometer (FPI), with an open micro-notch cavity fabricated by one-step femtosecond (fs) laser micromachining, for highly sensitive refractive index measurement. The device was tested for measurement of the refractive indices of various liquids including isopropanol, acetone and methanol at room temperature, as well as the temperature-dependent refractive index of deionized water from 3 to 90°C. The sensitivity for measurement of refractive index change of water was 1163 nm/RIU at the wavelength of 1550 nm. The temperature cross-sensitivity of the device was about 1.1×10−6 RIU/°C. The small size, all-fiber structure, small temperature dependence, linear response and high sensitivity, make the device attractive for chemical and biological sensing.

scholarly journals Influence of a Thermal Pad on Selected Parameters of Power LEDs

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3732
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak ◽  
Tomasz Torzewicz ◽  
Marcin Janicki
Keyword(s):  
Optical Properties ◽  
Thermal Resistance ◽  
Optical Power ◽  
Junction Temperature ◽  
Operating Parameters ◽  
Cold Plate ◽  
Optical Efficiency ◽  
Forward Current ◽  
Measurement Results ◽  
Set Up

This paper is devoted to the analysis of the influence of thermal pads on electric, optical, and thermal parameters of power LEDs. Measurements of parameters, such as thermal resistance, optical efficiency, and optical power, were performed for selected types of power LEDs operating with a thermal pad and without it at different values of the diode forward current and temperature of the cold plate. First, the measurement set-up used in the paper is described in detail. Then, the measurement results obtained for both considered manners of power LED assembly are compared. Some characteristics that illustrate the influence of forward current and temperature of the cold plate on electric, thermal, and optical properties of the tested devices are presented and discussed. It is shown that the use of the thermal pad makes it possible to achieve more advantageous values of operating parameters of the considered semiconductor devices at lower values of their junction temperature, which guarantees an increase in their lifetime.

scholarly journals Critical angle reflection imaging for quantification of molecular interactions on glass surface

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guangzhong Ma ◽  
Runli Liang ◽  
Zijian Wan ◽  
Shaopeng Wang
Keyword(s):  
Refractive Index ◽  
Small Molecule ◽  
Molecular Interactions ◽  
Glass Surface ◽  
Critical Angle ◽  
Dynamic Range ◽  
Refractive Index Change ◽  
Label Free ◽  
Index Change ◽  
Sensing Range

AbstractQuantification of molecular interactions on a surface is typically achieved via label-free techniques such as surface plasmon resonance (SPR). The sensitivity of SPR originates from the characteristic that the SPR angle is sensitive to the surface refractive index change. Analogously, in another interfacial optical phenomenon, total internal reflection, the critical angle is also refractive index dependent. Therefore, surface refractive index change can also be quantified by measuring the reflectivity near the critical angle. Based on this concept, we develop a method called critical angle reflection (CAR) imaging to quantify molecular interactions on glass surface. CAR imaging can be performed on SPR imaging setups. Through a side-by-side comparison, we show that CAR is capable of most molecular interaction measurements that SPR performs, including proteins, nucleic acids and cell-based detections. In addition, we show that CAR can detect small molecule bindings and intracellular signals beyond SPR sensing range. CAR exhibits several distinct characteristics, including tunable sensitivity and dynamic range, deeper vertical sensing range, fluorescence compatibility, broader wavelength and polarization of light selection, and glass surface chemistry. We anticipate CAR can expand SPR′s capability in small molecule detection, whole cell-based detection, simultaneous fluorescence imaging, and broader conjugation chemistry.

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