DTA

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Tesi etd-08242020-123748

Type of thesis
Master univ. I liv.
Author
KRISHAN, KIRANTI
URN
etd-08242020-123748
Title
Design and Characterization of Integrated Photonics Biochemical sensors
Structure
Istituto di Tecnologie della Comunicazione, dell'Informazione e della Percezione
Course
Corsi Alta Formazione - PHOTONIC INTEGRATED CIRCUITS, SENSORS AND NETWORKS (PIXNET)
Committee
relatore Dott. VELHA, PHILIPPE
Relatore Dott. SYGLETOS, STYLIANOS
Relatore Dott. SERGEYEV, SERGEY
Keywords
  • Biochemical Sensor
  • Mach-Zehnder Interferometer
  • Silicon Photonics
  • thermal phase noise
Exam session start date
;
Availability
completa
Abstract
The project targets a very important application which has a significant impact on quality of human life - Detection of contamination in drinking water.<br>The idea of this project was to study integrated optical biochemical sensors built on Silicon on Insulator (SOI) platform. Mach-Zehnder Interferometer was used as a basic building block for bio chemical sensing. The project walks through different problems encountered in achieving a highly sensitive device on a compact platform with minimum losses.<br> As MZI is highly sensitive to changes in refractive index due to environmental fluctuations, therefore, one of the part of this project was to detect different sources of noise responsible for the reduction of sensitivity in MZI, and a significant limiting factor was thermal phase noise.<br> Three different type of MZIs were characterized to analyze the performance of each type and different factors affecting the performance of each MZI. It was observed that thermal noise affected nearly all three types of MZI in a similar manner with a slight improvement of 20 dB in narrow MZI. Additionally, the sensitivity and dynamic range of MZI with narrow free spectral range (FSR) was quite better than the other two.<br>Another aspect of this project consist of designing a few passive components of MZI based biosensor at 1310 nm wavelength, which include Multi Mode Interference couplers and Grating couplers. This wavelength window was exploited to take advantage of lower water absorption in this wavelength range as compared to 1550 nm. It was observed that transmission of MMI coupler was $\sim$ 96-98$\%$ and in grating coupler it was $\sim$ 30-36 $\%$. Higher loss was observed in grating couplers as compared to MMI couplers. Grating coupler with TM mode experienced $\sim$ 6.7$\%$ higher loss than the grating coupler with TE mode. These couplers have been sent for fabrication and can possibly be integrated with a MZI at 1310 nm wavelength in future.<br>
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