Untitled in english

Author(s)

Acácio Luiz Siarkowski

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2001-11-29

Examining board members

Nilton Itiro Morimoto; Murilo Araujo Romero; Josemir Coelho Santos

• Advisor: Nilton Itiro Morimoto

Abstract

The aim of this work is the implementation of an integrated optical pressure sensor based on Mach-Zehnder Interferometer (MZI), using a microfabricated membrane on silicon substrate. Previous works, developed by our the research group, showed good results applying silicon oxide and silicon nitride thin films in the fabrication of waveguides and integrated optical sensors. To fabricate the integrated optical pressure sensor, the photolithography masks was designed, with the waveguides, MZIs and diaphragms patterns. The dimensions were based in the simulation results of the optical devices (BBV software) and mechanical deformation analyses (ANSYS software). The sensor structures were implemented on silicon monocrystalline substrates, using conventional microelectronics processes (thermal oxidation, chemical vapor deposition (CVD), optical lithography, plasma etching and wet etching). Physical and optical characterizations of the fabricated devices were performed. The fabricated optical pressure sensor showed a non-linear behavior between the static pressure applied on the silicon diaphragm and the laser output intensity. The sensibility and the pressure work range of the implemented optical sensor depend on the silicon diaphragm dimensions. Larger diaphragm dimensions gives better sensibility and shorter pressure work range. The scattering branching is higher of in the sensors implemented with higher aperture angles, which increases the noise level as well as decreases the stability and reproducibility during the optical measurements. (AU)