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Optical feedback sensing in microfluidics : design and characterization of VCSEL-based compact systems

Yu Zhao 1, 2
1 LAAS-OSE - Équipe Optoélectronique pour les Systèmes Embarqués
LAAS - Laboratoire d'analyse et d'architecture des systèmes
2 LAAS-MICA - Équipe MICrosystèmes d'Analyse
LAAS - Laboratoire d'analyse et d'architecture des systèmes
Abstract : Optical feedback interferometry (OFI) is an emerging sensing technique which has been studied in fluidic systems. This sensing scheme is based on the modulation of the laser emission output power and/or the junction voltage induced by the interaction between the back-scattered light from a distant target and the laser inner cavity light. Thanks to the Doppler Effect, OFI can precisely measure the velocity of seeding particles in flowing liquids which is much required in chemical engineering and biomedical fields. In the present thesis, optical feedback interferometry performance for microscale flow sensing is studied theoretically and experimentally. A new numerical modeling approach based on multi-physics numerical simulations for OFI signal simulation in the micro-scale flowmetry configuration is presented that highlight the sensor performances. In this model, many factors are involved such as particle concentration and laser-particle scattering angle distribution and flow velocity distribution. The flow rate measurement shows good agreement with the modeling. The implementation of OFI based sensors in multiple fluidic systems, investigating the impact of the fluidic chip specific configuration on the sensor signal.Finally, a compact OFI flowmetry sensor based on Vertical-Cavity Surface-Emitting Lasers (VCSELs) using micro optical fabrication techniques is demonstrated as well. The simulation method for the design and the microfabrication procedures are detailed. After an evaluation of the experimental results, the capabilities of this new OFI sensor in microfluidic measurements are emphasized, thus demonstrating an open path towards ultra-compact microfluidic systems based on the OFI sensing technique.
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Submitted on : Tuesday, June 26, 2018 - 3:10:41 PM
Last modification on : Monday, January 13, 2020 - 2:30:59 PM
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  • HAL Id : tel-01823859, version 1


Yu Zhao. Optical feedback sensing in microfluidics : design and characterization of VCSEL-based compact systems. Optics [physics.optics]. INSA de Toulouse, 2017. English. ⟨NNT : 2017ISAT0008⟩. ⟨tel-01823859⟩



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