High-aspect-ratio flat fiber for optofluidic lab-in-a-fiber sensing and bend-tunable refractive index enhancement
High-aspect-ratio flat fiber for optofluidic lab-in-a-fiber sensing and bend-tunable refractive index enhancement
A lab-in-a-fiber sensor platform is demonstrated, enabling simultaneous optical analysis and controlled microfluidic transport in a single monolithic device. It consists of a high-aspect-ratio flat fiber (HARFF) that integrates a mechanically compliant elliptical fused silica capillary and a Ge-doped single-mode waveguide. The waveguide, partially exposed to the capillary, provides evanescent field interaction with analytes introduced into the central microfluidic channel. The high-aspect-ratio microfluidic channel confines side wall effects, producing a flattened laminar flow that supports stable real-time imaging. Alongside particle-flow monitoring, the device exhibits a tunable refractive-index sensitivity. Through in-plane flexure, a more than three-fold sensitivity enhancement was demonstrated at a 50 mm bending radius over a straight fiber. This hybrid fiber sensor design represents cost-effective production of a compact and versatile platform for lab-in-fiber applications, combining optical interrogation and microfluidic functionality.
3205-3208
Maniewski, Pawel
fb31e508-188a-4034-a236-dd0a473874d0
Lee, Timothy
beb3b88e-3e5a-4c3f-8636-bb6de8040fcc
Vaccariello, Andrés M. Biondi
11268d9e-6c55-4297-b317-db0d980e2f9b
Beresna, Martynas
a6dc062e-93c6-46a5-aeb3-8de332cdec7b
Holmes, Christopher
2ec659eb-2bd3-460a-aa8d-5538eb1aeb25
28 May 2026
Maniewski, Pawel
fb31e508-188a-4034-a236-dd0a473874d0
Lee, Timothy
beb3b88e-3e5a-4c3f-8636-bb6de8040fcc
Vaccariello, Andrés M. Biondi
11268d9e-6c55-4297-b317-db0d980e2f9b
Beresna, Martynas
a6dc062e-93c6-46a5-aeb3-8de332cdec7b
Holmes, Christopher
2ec659eb-2bd3-460a-aa8d-5538eb1aeb25
Maniewski, Pawel, Lee, Timothy, Vaccariello, Andrés M. Biondi, Beresna, Martynas and Holmes, Christopher
(2026)
High-aspect-ratio flat fiber for optofluidic lab-in-a-fiber sensing and bend-tunable refractive index enhancement.
Optics Letters, 51 (11), .
(doi:10.1364/OL.597108).
Abstract
A lab-in-a-fiber sensor platform is demonstrated, enabling simultaneous optical analysis and controlled microfluidic transport in a single monolithic device. It consists of a high-aspect-ratio flat fiber (HARFF) that integrates a mechanically compliant elliptical fused silica capillary and a Ge-doped single-mode waveguide. The waveguide, partially exposed to the capillary, provides evanescent field interaction with analytes introduced into the central microfluidic channel. The high-aspect-ratio microfluidic channel confines side wall effects, producing a flattened laminar flow that supports stable real-time imaging. Alongside particle-flow monitoring, the device exhibits a tunable refractive-index sensitivity. Through in-plane flexure, a more than three-fold sensitivity enhancement was demonstrated at a 50 mm bending radius over a straight fiber. This hybrid fiber sensor design represents cost-effective production of a compact and versatile platform for lab-in-fiber applications, combining optical interrogation and microfluidic functionality.
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More information
Accepted/In Press date: 4 May 2026
Published date: 28 May 2026
Identifiers
Local EPrints ID: 512297
URI: http://eprints.soton.ac.uk/id/eprint/512297
ISSN: 0146-9592
PURE UUID: daff3a17-8b8b-475d-a759-43e39a9e7eda
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Date deposited: 23 Jun 2026 17:15
Last modified: 09 Aug 2026 01:23
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Contributors
Author:
Pawel Maniewski
Author:
Timothy Lee
Author:
Andrés M. Biondi Vaccariello
Author:
Martynas Beresna
Author:
Christopher Holmes
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