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Journal: Composites Part B-Engineering

Paper: Bonding sensor based on simpli ed Fiber Bragg Grating spectral evolution

AUTHORS: Luis Rodriguez-Cobo, Adolfo Cobo, Jose-Miguel Lopez-Higuera

Abtracts: A new bonding sensor for composite material manufacturing based on a single uniform Fiber Bragg Grating (FBG) is proposed and demonstrated in this paper. The sensor design includes two edge sections attached to the bonded parts and a central free region, all made of an epoxy resin block of constant thickness, where the FBG is embedded. The quality of this bond is quantified by measuring the FBG spectral evolution. The strain transfer from the sensor to the embedded fiber allows to distinguish between two typical bonding defects in composite structures: asymmetric deformation and slide of bonded parts. Both cases have been experimentally checked and the results are in good agreement with simulations based on a simplified model using the Finite Elements Analysis (FEA) and Transfer Matrix methods, even under complex deformations

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Journal: Biomedical Optics Express

Paper: Direct identification of breast cancer pathologies using blind separation of label-free localized reflectance measurements

AUTHORS: Alma Eguizabal, Ashley M. Laughney, Pilar Beatriz García-Allende, Venkataramanan Krishnaswamy; Wendy A. Wells, Keith D. Paulsen, Brian W. Pogue, Jose M. Lopez-Higuera, Olga M. Conde

Abracts: Breast tumors are blindly identified using Principal (PCA) and Independent Component Analysis (ICA) of localized reflectance measurements. No assumption of a particular theoretical model for the reflectance needs to be made, while the resulting features are proven to have discriminative power of breast pathologies. Normal, benign and malignant breast tissue types in lumpectomy specimens were imaged ex vivo and a surgeon-guided calibration of the system is proposed to overcome the limitations of the blind analysis. A simple, fast and linear classifier has been proposed where no training information is required for the diagnosis. A set of 29 breast tissue specimens have been diagnosed with a sensitivity of 96% and specificity of 95% when discriminating benign from malignant pathologies. The proposed hybrid combination PCA-ICA enhanced diagnostic discrimination, providing tumor probability maps, and intermediate PCA parameters reflected tissue optical properties


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Journal: Optics Express

Paper: Single-longitudinal mode laser structure based on a very narrow filtering technique

AUTHORS: L. Rodríguez-Cobo, M.A. Quintela; S. Rota-Rodrigo, M. Lopez-Amo, J.M. López-Higuera

Abstract: A narrow filtering technique based on the spectral overlapping ot two uniform FBGs and applied to obtain a Single Longitudinal Mode (SLM) laser is proposed and demostrated in the work. The two FBGs are spectrally detuned to reduce their coinciden reflection response narrowing the equivalent filter bandwidth. A proof-of-concept linear laser has been built and tested exhibiting SLM operation with temperature and strain variations. 

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