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Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

Adrian, Bradu and David, Jackson and Adrian, Podoleanu (2018) Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops. In: Podoleanu, Adrian and Bang, Ole, eds. 2nd Canterbury Conference on OCT with Emphasis on Broadband Optical Sources. Proceedings of SPIE . SPIE, Bellingham, Washington. ISBN 978-1-5106-1674-5. E-ISBN 978-1-5106-1675-2. (doi:10.1117/12.2282116) (KAR id:66336)


Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an “in-house” swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.

Item Type: Book section
DOI/Identification number: 10.1117/12.2282116
Projects: AdaSmartRes
Uncontrolled keywords: optical coherence tomography, re-circulation rings, long axial range, coherence length
Subjects: Q Science > QC Physics > QC355 Optics
T Technology > TA Engineering (General). Civil engineering (General) > TA1520 Applied optics. Photonics
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Funders: Engineering and Physical Sciences Research Council (
Marie Curie (
European Research Council (
University College London (
Depositing User: Adrian Bradu
Date Deposited: 09 Mar 2018 13:49 UTC
Last Modified: 12 Jul 2022 10:41 UTC
Resource URI: (The current URI for this page, for reference purposes)

University of Kent Author Information

Adrian, Bradu.

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David, Jackson.

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Adrian, Podoleanu.

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